In this work, a differential reactor was used to expose all the biofilter packing material (compost) to a uniform toluene concentration in air. The reactor was combined with water content control using the suction cell principle and traditional inlet concentration, temperature and humidity control. The matric potential was controlled using the suction cell principle between -5 to -300 cm H₂O which controlled the water content between 0.99 and 2.30 g g⁻¹ (dry weight). Two types of compost were used, with different water retention curves with no observed difference in elimination capacity. The elimination capacity varied between 2.7 g m⁻³r hr⁻¹ and 21 g m⁻³r hr⁻¹ with low potential causing low removal rates. The reduction in EC at low matric potentials was attributed to several factors: loss of water availability to the organisms, water redistribution in the medium, non-adaptable micro-organisms, and reduced mass transfer. Cultures isolated from compost were used to inoculate the reactor to create a biofilm. A maximal observed surface EC of is 0.17 g m⁻²r hr⁻¹ and a specific removal rate of 1250 g m⁻³b hr⁻¹ is measured. These values were used in modelling the biofilter performance. The EC was dependent on the residual toluene concentration. The EC increased with increasing toluene concentration until reaching a critical concentration. Above this concentration, 100 – 300 ppm (0.37- 1.11 g m⁻³) depending on biofilm thickness and area of coverage, the EC was constant. Three toluene dependency curves were fitted using a zero order and a composite model using a weighted average of a zero and first order component. From the data the critical concentration (Ccrit) and the ECcrit was found and used to determine the biofilm thickness. It was estimated to be between 68 and 134 µm. Using a qmax of 1250 g m⁻³b hr⁻¹ and optimising the model a Ks of 1.3•10⁻¹ g m⁻³g was found. This was comparable to values found in the literature. There was no significant difference in the fit between both models. The Ks was low compared to the majority of the data, which means that the zero order part of the composite model dominated. Nitrogen and other nutrients were added to investigate their influence on the elimination capacity (EC) of toluene. Also the effect of temperature on the EC was investigated between 14 and 60 °C. Maximal removal rates were found between 25 and 55 °C. The EC decreased by 90% going from 55 to 60 °C and took many weeks to recover. Without any extra nitrogen added to the media, the EC averaged around 6 ± 0.3 g m⁻³r h⁻¹. Although the average EC was lower than most reports for toluene removal, it was still in the general range reported. When NH4Cl (1 g l⁻¹) was added to the reactor, the EC increased to 41 ± 1.7 g m⁻³r hr⁻¹. Similar effects were observed with nitrate addition; the steady state EC doubled from 30.1 ± 0.9 g m⁻³r hr⁻¹ to 76.3 ± 2.5 g m⁻³r hr⁻¹. Other macronutrients tested like phosphate, sulphate, magnesium, calcium and iron did not increase the EC.

Contest outcomes are usually determined by differences in resource holding potential, the social histories of the combatants, and perceptions of resource value. One understudied aspect of gaining an advantage is the residency effect. Prior occupancy of a particular place can affect the knowledge and motivation of the resident. There could be a tactical advantage in knowing the terrain or an increased willingness to fight to maintain control of a familiar area. In this study we evaluated the importance of shelter residency effects relative to size differences between rusty crayfish (Orconectes rusticus) as potential competitors for access to shelter. The intensity of any residency effects was manipulated by altering the number of shelters in the arena. Our results suggest that any residency effect is very weak in this system, and if present may often be masked by the strong and pervasive influence on contest outcome of the relative body sizes of the contestants. We also found that both shelter number and crayfish size asymmetries had strong, independent effects on levels of aggression. Dominance, but not residency status, was a factor in shelter use.

No description available.

This thesis reports the: cross section, parameterized differential cross section, and analyzing power (a.k.a. the photon asymmetry), for neutron production via the photodisintegration of the unpolarized deuteron at 18 MeV using linearly polarized photons. The data were collected in October 2010 using the High Intensity Gamma Source at the Duke Free-Electron Laser Laboratory located at Duke University in Durham, North Carolina. The ejectile neutrons from the photodisintegration reaction were measured using the Blowfish detector array: a spherical array of 88 BC-505 liquid organic scintillator cells which cover approximately pi steradians. The initial goal of our experiment was to perform tests on the detector characteristics and check a few potential sources of systematic error, and so uncontaminated experimental runs were only taken with the remaining beam-time. Our data are therefore not optimized for precision, and so presented a number of data analysis challenges. This thesis delineates the challenges and respective solutions. Contrary to earlier results near deuteron binding energy threshold, we see reasonable agreement with a theoretical calculation based on retarded one meson exchange with empirical cutoffs in the propagators, including: off-shell corrections, relativistic corrections and the Delta isobar degree-of-freedom. Our results show similar agreement to theory as previous experiments at 14 and 16 MeV, although we see no target length dependence: such has been observed at 20 MeV.

Falkenberg area is located in southwest Sweden formed in the Sveconorwegian orogen and contains an extremely complex geological structure. Multiple geophysical datasets have been acquired and together with available petrophysical information, models corresponding to the subsurface geological structures were generated. The collected data comprise ground magnetic, AMT (Audio Magnetotelluric) and RMT (Radio Magnetotelluric) data. The available airborne magnetic and ground gravity data acquired by the Geological Survey of Sweden (SGU) as well as the reflection seismic section from a study made by Uppsala University further aids in obtaining substantially improved interpretation of the geometry of the structures along the AMT profile. The principal objective of this profile was to delineate and map the possible deformation zone crossed by the profile. The AMT study was expected to complement existing geophysical data and improve existing interpretations. The Ullared deformation zone contains decompressed eclogite facies rocks. The presented results were obtained by comparison of different geophysical methods along the profile. The susceptibility model and resistivity model show that eclogites have higher resistivity and susceptibility than the surrounding structures. However use of the Occam type of inversion on the AMT data, makes the resistivity model smoother than the susceptibility model and as a results it is difficult to estimate the dip of the structures. The AMT profile and the seismic section show the same dip direction (NE) for the eclogite bearing structures although due to the smoothing in the AMT model the dips seen in the seismic section cannot be recovered in the resistivity model.

My overall claim in this paper is twofold: Firstly, the activity of developing arguments in favour of the existence of the Christian God is tenable and worthwhile and, secondly, the “infinite God objection” fails to undermine the kalam cosmological argument. Concerning the former, it is often claimed that the very activity of developing arguments in favour of God’s existence is futile. I argue, however, that such theistic arguments play an important role in the philosophy of religion, natural theology, and apologetics. Concerning the latter claim, I will attempt to show how the infinite God objection fails to undermine a notable theistic argument, namely, the kalam cosmological argument. As regards this objection, the proponents of the kalam cosmological argument face a dilemma – either an actual infinity cannot exist or God’s knowledge cannot be infinite. More specifically, this objection claims that God’s omniscience entails the existence of an actual infinity with God knowing an actual infinite number of future events and mathematical truths. My solution to this problem is that (1) God’s omniscience should be understood as maximal knowledge; (2) the existence of abstract objects (such as numbers and propositions) should be denied; and (3) God’s knowledge is non-propositional in nature. / MPhil, North-West University, Potchefstroom Campus, 2014

The thesis describes development and optimization process of an inductively coupled coil corrosion potential sensor for long-term civil structure health monitoring remotely. This is of growing interest for decreasing the maintenance cost, reducing the deterioration significantly and increasing the safety. The thesis is organized accordingly introduction, circuit modeling of the sensor, optimization and fabrication of the sensors and the simulated and experimental results from new and existing civil structure. The two geometrical design, cylindrical shape and Printed Circuit Board (PCB) based sensor parts of this research and their encapsulation technique for long-term enduring in harsh and corrosive environment of the civil infrastructure is described in the thesis. Results of an accelerated corrosion test on an embedded cylindrical shaped sensor indicates that the corrosion potential can be monitored with less than 10 mV resolution with a sensor sensitivity of ~0.73 kHz/mV. The last part describes a novel technique for a PCB sensor to simulate the existing structure already contaminated with corrosive substances such as chlorides. Two encapsulation techniques, non-conductive epoxy sealed and PLEXIGLAS with air gap sealed embedded PCB sensors response are compared from the accelerated corrosion test on new and built-in civil structure. Finally, results from the accelerated corrosion tests using the two encapsulation techniques mentioned above demonstrate that the embedded sensor in an existing structure may take up to 60 days to see the significant corrosion with a sensor sensitivity of ~ 1.53 kHz/mV or ~ 1.63 kHz/mV respectively. Since chlorides take many years to diffuse into concrete used for civil structures these sensors will respond fast enough to be used in existing structures as well as in new structures.

South Africans leaving their country of birth is not a new phenomenon. South Africa currently has a large shortage of engineers and the fact that engineers are seeking better opportunities abroad is worsening the skills shortage in South Africa. Engineers form a vital part of any manufacturing, design, supply or production entity and leave a large setback if a skilled, experienced engineer decides to emigrate. Official statistics from self-declared emigrants showed that 601 engineers out of the total 16,165 self-declared emigrants left the country in 2003. This figure can be double the given number of 601 if the multiplication factor of 2.0 is taken into consideration for people that do not complete the emigration forms at the airports. The focus of this study was to investigate the emigration potential of the skilled engineer along with the factors that might lead to emigration, and were classified into three distinctive groups, namely, economic, political and social. These aspects are generally referred to as "push" factors that drive people out of the country such as racism, crime and violence; as well as "pull" factors that attract people such as better work opportunities, better salaries and better education. An electronic survey questionnaire was used to determine the emigration potential of the engineers within a large mining organisation. The respondents had to indicate their emigration potential as well as the major factors that would contribute to them leaving South Africa. The overall measured potential for emigration within the specific mining organisation was significantly low. Only twenty percent of respondents agreed that they are planning to emigrate within the next five years and only two percent within the next year. Forty-six percent of respondents agreed that they would rather like to work in another country for only a few years than to emigrate permanently. Various reasons could have lead to the contradicting low measured emigration potential within this specific organisation. Literature has proven that there is a significant relationship between intention to emigrate and organisational commitment. Results also showed that emigration potential tend to increase the better the engineer is qualified; with the emigration potential amongst electrical and mechanical engineers higher than all other disciplines. Crime and violence were the number one factor impacting the respondent in terms of potential emigration. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2010.

Forest rings are large features common in Ontario’s boreal forests that comprise circular topographic depressions in carbonate mineral soil that are filled with peat. This thesis documents differences in peat and soil chemistry along transects across the “Bean” and “Thorn North” rings, which are centered on accumulations of CH4 and H2S, respectively. Within the mineral soil, ring edges are characterized by strong negative anomalies in pH, ORP and carbonate, as well as positive anomalies of Al, Fe and Mn in the results of aqua regia and hydroxylamine-hydrochloride digestions. Within the peat, positive carbonate and pH anomalies are recorded. This antithetic relationship suggests vertical migration of carbonate species from clay to peat. An inverse relationship exists between ORP, versus redox inferred from aqua regia. Strong ORP lows occur where oxidized products show highest concentrations. This is interpreted to reflect the proliferation of autotrophic organisms occupying the strong redox gradient at the ring edge.

South Africans leaving their country of birth is not a new phenomenon. South Africa currently has a large shortage of engineers and the fact that engineers are seeking better opportunities abroad is worsening the skills shortage in South Africa. Engineers form a vital part of any manufacturing, design, supply or production entity and leave a large setback if a skilled, experienced engineer decides to emigrate. Official statistics from self-declared emigrants showed that 601 engineers out of the total 16,165 self-declared emigrants left the country in 2003. This figure can be double the given number of 601 if the multiplication factor of 2.0 is taken into consideration for people that do not complete the emigration forms at the airports. The focus of this study was to investigate the emigration potential of the skilled engineer along with the factors that might lead to emigration, and were classified into three distinctive groups, namely, economic, political and social. These aspects are generally referred to as "push" factors that drive people out of the country such as racism, crime and violence; as well as "pull" factors that attract people such as better work opportunities, better salaries and better education. An electronic survey questionnaire was used to determine the emigration potential of the engineers within a large mining organisation. The respondents had to indicate their emigration potential as well as the major factors that would contribute to them leaving South Africa. The overall measured potential for emigration within the specific mining organisation was significantly low. Only twenty percent of respondents agreed that they are planning to emigrate within the next five years and only two percent within the next year. Forty-six percent of respondents agreed that they would rather like to work in another country for only a few years than to emigrate permanently. Various reasons could have lead to the contradicting low measured emigration potential within this specific organisation. Literature has proven that there is a significant relationship between intention to emigrate and organisational commitment. Results also showed that emigration potential tend to increase the better the engineer is qualified; with the emigration potential amongst electrical and mechanical engineers higher than all other disciplines. Crime and violence were the number one factor impacting the respondent in terms of potential emigration. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2010.