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Sensed and actual posture of Grade 5 learners while carrying a schoolbag
No full textBackground: The main aim for the current study was to stablish the difference between sensed and actual posture while a Grade 5 learner is standing and carrying a schoolbag. Sensed posture is invisible and is dependent on the person who senses it; while actual posture is considered as the postural alignment that is visible to others. Due to the difference between sensed posture and actual posture, understanding how the two differ and how the body senses its posture as opposed the actual posture, will influence correct postural control on a child's body and their joint positioning in standing, walking and activity engagement and therefore promote physical wellbeing of the children. Despite a few single-joint studies done on the concept of sensed and actual posture, no study investigated sensed and actual posture in children with respect to whole body postural alignment, especially when they carry a backpack. Methods: A descriptive cross-sectional study design was used in the current study. The study population consisted of 198 primary school learners in Grade 5. Participants had similar socio-economic status and were between the ages of 9.6 and 13.5, both boys and girls were included. The researcher used the Photographic Method of Postural Assessment (P-MPA) for assessment of postural alignment. The P-MPA was proved to accurately measure deviations between anatomical landmarks and the line of gravity, and also proved to be reliable in terms of reproducibility. In the set-up for the P-MPA, the participant assumed a position at 1 meter behind the plumb line, with the plumb line aligned with the lateral malleoli for the lateral standing position, and with the mid heels for the anterior standing position. The participant was asked to assume his/her most natural standing position. Photographs were taken by the researcher from 2m distance with a smartphone that was fixed on a tripod at a height of 950mm. Photographs were later printed and actual posture on the photographs was measured and results were captured on an excel spread sheet. The actual (real) distance on photos was established by calculating the ratio of measured (real) distance x distance from plumb line for each photo. A clinical significant difference from the reference point as measured on the photo was set at 10mm. The coding was done by the researcher, followed by data analysis. Descriptive statistics, namely frequencies and percentages for categorical data, medians and percentiles for numerical data, were calculated. The sensed and actual deviation at each landmark, was compared by means of 95% confidence intervals (Cl) for median differences for paired data. Results: Results indicate that there was no significant difference observed on all the anterior views with reference to the difference between sensed and actual posture for the respective anatomical landmarks. Evidence from this study further indicate that sensed and actual posture differ when observed from lateral view, especially when weight is involved, in this instance; when a learner is carrying a backpack. Besides the remarkable clinical and statistical difference on the affected landmarks, the earlobe demonstrated significant difference more regularly than other anatomical landmarks; mid knees, greater trochanter and acromion process on the lateral views. Noticeably, the values of deviations increased per anatomical landmark moving from lower anatomical landmark; lateral malleoli to higher anatomical landmark; earlobe. Lastly, in most instances the anatomical landmarks that displayed significant difference on the left side also displayed a difference on the right side. Biographical questionnaire results indicate that 53% of participants compensate by bending when carrying a backpack, of whom 88.3% stated that they bend involuntarily. Conclusion: Results from this study indicate the difference between sensed and actual posture while a Grade 5 learner is carrying a backpack, for all the respective landmarks noticeable from lateral views. These differences contribute to the knowledge base of factors that may have an impact on the learner's developing spine and wellbeing. It is recommended that these results be aligned with the lntergraded School Health Programme (ISHP) and to complement intervention strategies in order to enhance the wellbeing of individuals in school setting and the community at large.Department of Occupational TherapyUFS Post Graduate Schoo
Modelling reactive pollutant transport in ground water: the case of two species
No full textThe locations of a significant number of industrial facilities, landfills and almost all mineral ore bodies are characterised by high in situ stresses and fractures and fissures act as flow paths for fluids underground. Regional scale fracture systems that transport pollution from spatially isolated source locations can cause mixing of chemical pollutants from different source origins due to fracture- fracture flux across two or more intersecting fractures, hence reactive transport. Alerts of groundwater contamination in response to multicomponent pollution transport have been investigated using a mathematical model of the hydrodynamic response of incompressible fluids such as groundwater flow. Fundamental to the model is the conservation of mass associated with the applied source strength and the concentration velocity field redistributions after source has released pollution, assuming the formation is homogenous. Solute distribution depends on the formation porosity and generally, fluids travel faster in fractures than in sedimentary formations. Different variations of the deterministic advection dispersion equation have been employed to predict coupled transport/reactive processes by substitution of a reaction term (retardation factor, etc..) which accounts for the changing concentration of the solid face components through time due to chemical reaction. However, fractured aquifers are inherently heterogeneous due to interconnecting fractures. The results in a non-homogenous mathematical formulation which difficult to solve analytically. As a result, most research endeavours have tended to depend on numerical solutions, increasingly made possible through advanced computational power. Even though it is questionable to what extend numerical models of groundwater reactive transport can be useful in making accurate quantitative predictions, it is still possible for a reactive model to predict the outcome of a particular chemical representation in an aquifer. Nevertheless, the linear, non-homogenous advection dispersion equation can still be solved analytical using the Green’s function method.
In this thesis, we show how the advection-dispersion transport equation can be extended to account for geochemical reaction processes in a heterogeneous media. For the hypothetical case study, the system was made of a homogenous and a non-homogenous sub-component. The study’s methodological approach involved coupling of the homogenous transport phase with the non- homogenous system. The solution of the homogenous equation is obtained using Laplace transform and the exact solution of the new non-homogenous equation is obtained analytically using Laplace transform and the Green’s Function method. Both sub-models were solved numerically using the Crank-Nicolson discretization scheme and their stability conditions also established. For the proposed fracture flow system, the linear non-homogenous model was able to approximate the contribution of reactive transport processes in the system. Chemical reactions can attenuate the spread of a contaminant plume due to processes such as sorption and precipitation. The model presented in this thesis was able to predict fate of each species within the system. Mass transfer during and after the reaction resulted in the depletion of one source with respect to another, which the model showed positive results in capturing. The thesis concludes with a chapter on chemical equilibria which is the basis of kinetic modelling and the understanding of the progress of chemical reactions
Environmentally friendly rhodium(I) model catalysts
No full textThe aim of this study was to investigate model rhodium(I) complexes as environmentally friendly water-soluble homogeneous catalysts for processes such as the carbonylation of methanol, a process that is important in industry due to its role in i.e. the production of liquid fuels and bulk chemicals. The flexibility of manipulating tertiary phosphines in terms of bulkiness and Lewis basicity are factors which render them attractive candidates in the modification of square-planar complexes towards applied chemical processes. If the latter are utilized in homogeneous catalytic applications, different fundamental and bench-marking reactions are of importance such as substitution reactions and oxidative addition. A range of 4-(phenylamino)pent-3-en-2-onate (PhonyH) derivatives with various electron withdrawing and donating substituents on the para position on the N-phenyl ring were synthesized and characterised with infrared and NMR spectroscopy. The uncoordinated compounds were then used to synthesis a range of dicarbonyl-[4-(phenylamino)pent-3-en-2onato]-rhodium(I) complexes. Following the synthesis of the dicarbonyl-rhodium(I) complexes, tertiary phosphines, PR3 (PR3 = triphenylphosphine (PPh3) and 1,3,5-triaza-7phosphaadamantane (PTA)) were employed to substitute a CO from the parent complexes, forming carbonyl-[4-(phenylamino)pent-3-en-2-onato]-PR3-rhodium(I) [Rh(N,O-bid)(CO)(PR3)] complexes. Single crystal X-ray crystallographic determinations of the [Rh(4-CH3Phony)(CO)(PPh3)] and [Rh(4-F-Phony)(CO)(PPh3)] complexes were successfully completed and compared with literature. [Rh(4-CH3-Phony)(CO)(PPh3)] crystalized in the triclinic (P1) crystal system, whilst [Rh(4-F-Phony)(CO)(PPh3)] crystalized in the monoclinic space group (P21/c). A preliminary kinetic study of the CO substitution reaction and equilibrium studies were undertaken to evaluate how changes at the rhodium(I) centre could affect the reactivity of the rhodium(I) complex. Similarly, a preliminary kinetic study of the iodomethane oxidative addition to [Rh(4-CH3-Phony)(CO)(PPh3)] and [Rh(4-CH3-Phony)(CO)(PTA)] was undertaken to evaluate the reactivities of these Rh(I) model complexes. Through the substitution kinetic studies it was discovered that a large equilibrium constant (K1) was present favouring the formation of the [Rh(4-CH3-Phony)(CO)(PTA)] as product, but further investigation was identified to clarify some uncertainties due to the presence of other preliminarily identified but unknown species also present. The preliminary kinetic study of the iodomethane oxidative addition showed that the Rh(III) alkyl species which forms from the first product from the [Rh(4-CH3-Phony)(CO)(PTA)] species exhibits a larger equilibrium constant value (K1) than that obtained for the corresponding [Rh(4-CH3-Phony)(CO)(PPh3)], although not that significant. Nevertheless, similar experiments when evaluating the [Rh(4-CH3-Phony)(CO)(PTA)] as reactant confirmed its reactivity similar to the PPh3 analog and hence the potential application for the design of future water-soluble catalyst models.University of the Free StateNational Research Foundation (NRF
The politics of sustainability: discourse and power in post-2000 Zimbabwean political texts
No full textDiscourse (language in social context) has ‘dimensions’ that make and unmake power. Power is created, sustained and contested through language. This is mainly because by its nature, if not forcibly acquired, power is discursively attained. As the chief mechanism of enabling (and also disabling) power, discourse is an indispensable site to understand Zimbabwean politics and policies shaped by the economic crisis of the post-2000 period. Yet despite its important significance and function as a medium of self-articulation and identification, very little research has been done on the potential of discourse approaches to dynamics and dimensions of the Zimbabwean crisis. Shifting focus to previously unstudied sites of Zimbabwean political discourse (political texts - mainly party manifestos), this study extends what is known about the uses of rhetoric and discourse in guiding perceptions and conceptions of the crisis and connected to that, the making, sustenance and unmaking of power. The question that this thesis answers concerns how, what is said as part of political promises makes political sense vis-à-vis the urgency of containing the crisis and, related to that, gaining or maintaining power to run the nation. This involves a careful analysis of rhetoric to ascertain the political function of discourse in concretising certain conceptions of the crisis, how it can be addressed and who is (and is not) best suited to address it. At the centre of the crisis discourse in Zimbabwe is the agenda for sustainable socio-economic development and contestation for power. In contemporary Zimbabwe, sustainability is a concept that has taken a wide range of meanings, inter alia, because of its natural relevance to economic development paradigms in the face of the economic crisis characterising the post-2000 period. Central to the concept of sustainability discourse are political promises to deal with the crisis, eradicate poverty, protect the environment, address equity imbalances and safeguard national sovereignty. However, underlying discourses on sustainability are numerous conflicting assumptions and guidelines for action. Such contradictions emanate from the fact that in a crisis situation, what is sustainable vis-à-vis strategies for economic recovery is often political and politicised, thus policies on sustainable national development are (re)packaged, (re)modelled, and (re)presented to serve both institutional (party) politics and policies. That Zimbabwe has been experiencing an economic and political crisis is not the debate; rather, what is in question concerns what necessary interventions are needed and adjunct to this, who is best situated to intervene. These are the questions that political parties, such as, the ruling party, Zimbabwe African National Union – Patriotic Front (ZANU PF) in #Team ZANU PF (2013), Zimbabwe Agenda for Sustainable Socio-Economic Transformation (Zim Asset) (2013) and The People’s Voice (2018); and oppositional parties such as the Movement for Democratic Change (MDC) in Jobs, Upliftment, Investment Capital and Environment (JUICE) (2013), Zimbabwe People First (Zim PF) and National People’s Party in Blueprint to Unlock Investment and Leverage for Development (BUILD) (2015) and People’s Rainbow Coalition (PRC) in Inclusive Development Agenda (IDEA) (2018) are grappling with in contemporary Zimbabwe. The questions have informed policy and more importantly (with regards to this study’s focus) the discourse of policy. Guided mainly by Fairclough’s theorisation on the ways in which representing reality is informed by and reflect (on) ideologies impacting various forms of power relations, this study explores the politics of rhetoric in post- 2000 Zimbabwe. The study asks the following questions: what is the nature of the Zimbabwean crisis as perceived from the various political vantage points in political texts; what characterises the rhetoric on who and/or what is responsible for the crisis; what are the discursive strategies used by parties to influence people to align with certain interpretations of the crisis (believability) and suspect others, and lastly, how does a discourse-focused approach to the politics of representing the Zimbabwean crisis refresh modes and epistemologies of knowing its nature, historical trajectory and how it has shaped policy and political practice in contemporary Zimbabwe?University of the Free State (UFS
Toolkit-based framework for scalable High Performance Standalone Molecular Dynamics simulations
No full textComputational modelling and simulation in materials science uses mathematical abstractions
of particle-particle forces to postulate, develop and understand materials that are organized
as particle systems. Real particle systems occupy macroscopic scales and can be costly to
simulate in terms of hardware and software tools and simulation time. Even the most basic
simulation can generate large amounts of intermediate data that requires innovative further
processing to decipher its underlying physics or to answer fundamental questions about its
material properties. These questions are increasingly being asked due the present furious
academic and industrial interest in nanosized crystalline lattices. Of particular pertinence are
questions of whether or not the properties of the nanostructures are identical to those of their
macrostructures. In the light of this the primary focus of this contribution is the development
of a tool to simulate face-centered cubic (fcc) particle systems on a “standalone” hardware
platform, and to apply it to a specified particle system. The studied particle systems are to
range from nanostructures to macrostructures.
This thesis is thematically divided into two main parts. In the first part, comprising the
first five chapters, we conduct a detailed survey of the current in computation, followed by a
definition of the kinds of systems to which the study is applicable, and then we provide a
detailed but not overwhelming description of the tool development, with numerous actual
codes and examples. This part culminates in a working tool, abbreviated VSV. In the second
part, comprising the subsequent chapters, we apply the VSV and associated tools to solve actual physics problems in nanostructures thereby offering new approaches and results to
answer the current questions.
In developing VSV, we discuss the pairwise-particle potential and its integration into an
embedded atom model (EAM) approach that is a cost-effective way to simulate fcc metallic
lattice systems as a select case that has practical and industrial relevance. To do this, We
chose the Sutton-Chen EAM as being suitable. This was followed by the application of VSV
on a single computer as the “standalone” setting, and then on a small, four-computer cluster
consisting of multi-core, multi-processors to test its scaling and parallelization. The test
system consisted of 30,261 copper atoms in an arbitrary fcc lattice. The various simulations
were then evaluated for performance enhancements in terms of execution speed and ease of
application. The large amounts of intermediate data made it necessary to develop smaller
extensions to the VSV tool to enable output visualization. These extensions were written in
Visual Basic and Matlab. We then apply VSV to simulate the systems at low energies and
suggest novel answers to various questions within the framework mentioned above.
A first major, unwittingly observed result in the application of VSV is that it showed
that bond lengths between any two particles appear to develop a temporal oscillation when
perturbed by a nearby displaced atom. These oscillations are seen to propagate throughout
the lattice and eventually form a standing wave pattern, through which temperature can be
modelled. By applying perturbations in which the bond length oscillation amplitudes are
constrained to small values by deliberately applied perturbations, we found that the use
of an elastic, Hooke’s Law model results in a faithful reproduction of the known elastic
constants for the copper material on which it was tested. Thus, we suggest and develop a
unique impulse and oscillation method that is useful to calculate the elastic properties of
fcc nanostructures. A second result is the extension of this impulse-oscillation method to
postulate a way to initiate wave-like energy transfer through the lattice. These waves are
shown to be phonons and by constraining the energy to the first Brillouin zone we show that the temperature behavior of the lattice can be estimated. A third result is that VSV enables
the computation of the diffusion in a nanosized lattice. Furthermore, we apply standard
diffusion models to a low temperature regime and calculate the diffusion constants of the
lattice using standard models. An important result is the indication that diffusion in such a
collection of atoms in not driven by Brownian motion, but by the interplay of pair-wise 12-6
forces. We also show that the lattice atoms can spontaneously coalesce into a shape that is
guided by the global minimum of potential energy. Finally, VSV also shows how growth
into bigger fcc structures can be simulated through atom captures.
The foregoing results are compared with the literature values and the good agreements
indicate that it as a reasonable new and cost effective way to investigate many of the properties
of fcc lattices. Aspects of the research have been published in a book chapter, journals and
presented at international conferences.
Finally, we present the concluding remarks about research and suggest further directions
in terms of further development of VSV and its applications to new and novel structures
A sustainable farm management model for land reform in Mpumalanga, South Africa
No full textThe overall objective of the study was two-folded, firstly to develop inclusive sustainable and appropriate farm management model for land reform farming enterprises and secondly, to contribute considerably to rural development and the improvement of livelihood of rural people and land reform beneficiaries in Mpumalanga Province. In order to reach its objectives, the study started by reviewing literature on land reform. This was followed by a socio-economic-analysis to identify the main agricultural social and economic opportunities and factors inhibiting sustainable development in the province as well as performance and sustainability of commercial cooperatives and sole proprietorships citrus farms, the elements of success and failure in the CPA’s, state owned and small subsistence family farms and assessment of elements that promotes true sustainable citrus farming in Mpumalanga Province. Participants were sampled from five major categories of sampling frameworks and these included communal farmers defined as land reform beneficiaries (commonly known as CPAs) who acquired their farms through land redistribution programmes and households farmers defined as land reform beneficiaries, households that has acquired their farms without any support from state led approaches such as land reform programmes (sole proprietorships), private commercial cooperates which are producing citrus and state institutions which owns and manages citrus enterprises. However, only 190 farmers were eventually selected through stratification to participate in the study based on their willingness to take part. The breakdown of farmers who participated in the study, according to all three citrus regions in Mpumalanga Province, were 134 communal farmers (CPAs), 10 household farmers benefited from land reform, 20 private households famers, 20 private commercial cooperates and 06 state owned enterprises. The results showed that the business models promoted as part of both cooperatives and sole proprietors have succeeded in producing sustainable enterprises or distributing benefits to the shareholders. From Mpumalanga’s perspectives, the assessment of performance and sustainability of cooperatives and sole proprietorships appears to be largely positive. Enough material progress has been made in any of the cases outlined here to conclude that this type of farming enterprises are performing well or are delivering sustainable benefits to the shareholders over time. Despite a discouraging period; including land reform and unfavourable conditions for production as a result of climate change, it is clear that some fundamental progress have been made in the design and implementation of these enterprises. On the cooperative side, a detailed business plan, management model are adhered to and the mangers that are employed has farming skills and knowledge and cooperatives are able to deal with increased protectionisms. On the sole proprietor’s side, little firm commitments as comparing to cooperatives have been made regarding investment on employing managers with farming skills and knowledge, tackling the ever increasing international protectionisms and putting in place a detailed business plan. The main strengths of CPAs farms were: (i) the availability of a well-established export infrastructure (78%); (ii) access to export infrastructure facilities (76%); (iii) sufficient technology within the farm’s pack-houses (63%); and (iv) meeting of accreditation standards such as Good Agricultural Practice (GAP) certification (63%). Land reform households’ farms were faced by many weaknesses and threats than strengths. Although, the main strength for state owned farms were: (i) the availability of a wellestablished export infrastructure (67%); (ii) access by farmers to export infrastructure facilities (67%); (iii) sufficient technology within the farm’s pack-houses, good quality of the produce, and meeting of accreditation standards such as GLOBAL GAP certification (50%). All the farms under the study were failing due to high costs of farming inputs. At least 100% households’ land reform farms, 100% of commercial cooperatives, 100% of sole proprietors, 94% of CPAs, and 67% of the state owned farms were not sustainable as a result of inability to graduate from emergent to a commercial level. Moreover, the majority of CPAs (83%) and household farms (60%) were not equipped with the farming skills and farming knowledge. In terms of communication with stakeholders, majority of CPAs (73%), land reform households farms (90%) and state owned farms (67%) had a poor communication with key project sponsors. Land reforms households were faced with many challenges than CPAs and State owned farms combined. About 80% of the farms had no access to export infrastructure, while 90% of these farms produces citrus of a poor quality as compared to their counterparts. Only 10% had access to pack-house with modern technology and meets the accreditations standards. A significant percentage (46%) of the CPAs has access to new export markets. Furthermore, majority (59%) of the CPAs product is in high demand. The main threat facing farmers across all the three categories was cost and availability of water for irrigation. For example, households (100%), CPAs (99%), and state owned farms (83%). Of the CPA’s and land reform households’ farms respondents, 60% of CPAs and 100% of land reform households’ farms were confronted with competition from new entrants. In addition, 84% of CPAs, as well as 100% of household farms were choking with high protectionisms from external or international markets. On the whole, this study revealed, the need to have a comprehensive business plan with more emphasis on certain areas, such as operational/product plan, organization and staffing plan as well as risk planning to ensure true sustainable citrus farming. It revealed the need to improve education more particularly by acquiring at least secondary or tertiary education and farm management hierarchy must include youth. This study indicated areas of management, more particularly the principal activities of every farm management tasks that managers has to adhere, such as control, coordination and organizational/implementation. The study also raised land tenure or right to use land systems that need urgent attention. Title of communal land must be transferred to farmers, either as groups or individually. Those who are appointed to manage farming enterprises must have both technical knowledge and practical experience. Technical skills may include product management (be it a crop or livestock) to a level where it appeals to the market. The farmers must be exposed to these skills at a very young age. Farm managers should at least have more than eight in farming. Managers must be more capable of making most of the new opportunities by employing good technics in exploiting those opportunities and be able to handle new threats that would have been brought by changes in climate, technology, the economic climate, new legislation protecting the consumer. The conclusion is that the cooperatives and sole proprietors are sustainable and the chances of ensuring that CPAs, land reform farms and state owned farms are sustainable were most favourable for farmers who has responsive farm management model; would develop model that would properly influence the whole farm business planning to ensure sustainability of farms and shy away from the tendency of compiling business plans for government to release funds, but to represent the roadmap for the future. And those in executive positions would participate in the drafting of business plan; listing of farming risks with possible risk management strategies and recruitment of skilled and knowledgeable managers. Finally is recommended that the farming business must be treated as a commercial business in order to maximize outputs through effective agricultural practices that maximize income
Elderly people’s subjective experiences of relocation to residential care facilities
No full textIn this study, the subjective experiences of older persons who relocated to residential care facilities were investigated. During Apartheid South Africa, only White elders were accommodated at most residential care facilities and the previously disadvantaged was excluded. Furthermore, previous research focused mainly on the experiences of the wealthier white groups; consequently, this study focused on the middle-to-lower income groups, including Black elders. Considering the diverse and often adverse circumstances at South African residential care facilities, it is essential to consider the relocation experiences of elders in such facilities, and what experiences contribute to their sense of home. Such information would help to equip those caring for the needs of older people with knowledge that will benefit the well-being of elders. Literature regarding ageing and relocation during late adulthood was utilised to conceptualise the concept of relocation. Experiences and related issues regarding the process of relocation to a residential care facility were viewed from an interpretivist perspective.
A qualitative framework was chosen to give individuals experiencing this move a voice. A focus group approach was used, and semi-structured sessions were held to discuss participants’ experiences of relocation openly. Twenty-five participants took part in this study. They were identified by means of a non-probability sampling method, namely purposive sampling. Data were analysed and interpreted by means of thematic analyses, and various themes and subthemes emerged from the data sets. The findings of this study correspond with previous research that indicates that relocation experiences entail a process that encompasses factors prior to relocation, which contributed to the participants’ decision to relocate to residential care facilities, generally classified under push and pull factors. Other themes that correspond with previous research are factors relating to the adaptation process as well as participants’ experience of the move to, and living at residential care facilities
Fighting cancer with metals: main focus on Rhemium(I) complexes
No full textIn recent years, photodynamic therapy (PDT) has aroused significant interest as a
potential method of treatment for certain cancers. A non-intrusive treatment, PDT
consequently overcomes various obstacles of currently available treatment methods,
notably toxicity. However, PDT is not without its limitations. These include, although
they are not limited to, low selectivity and an inability to penetrate deep tissues. To
overcome such shortcomings, a range of rhenium(I) compounds of the type fac-
[Re(CO)3(N,N’-bid(X)]n and cis-trans-[Re(CO)2(N,N’-bid)(X)2]n (n = 0, +1) were
synthesised, most of which displayed good yields, ranging from 38.10 to 85.90 % for
tricarbonyl and 12.80 to 80.30 % for dicarbonyl complexes, and characterised. Four
bimetallic complexes [(Cl2)Pt(O,O’-phenO2-N,N’)-Re(CO)3(Br)], [(Cl2)Pd(O,O’-
phenO2-N,N’)-Re(CO)3(Br)], [(Cl2)Pt(O,O’-phenO2-N,N’)-Ru(bpy)2][PF6]2∙2H2O, and
[(Cl2)Pd(O,O’-phenO2-N,N’)-Ru(bpy)2][PF6]2 ∙ 2H2O were synthesised and
characterised. However, low yields ranging from 10.66 to 45.52 % were obtained.
Two 99mTc complexes, cis-trans-[99mTc(CO)2(bpy)(PPh3)2]+ and cis-trans-[99mTc(CO)2(bpy)(PTA)2]+ were synthesised and isolated with retention
times of 16.928 and 11.385 minutes respectively.
The crystal structure of fac-[Re(CO)3(bpy)(Br)] was obtained and solved and is
reported in this study. The rhenium to nitrogen bond distances (Re1-N1, Re1-N2) are
reported as 2.171(4) Å and 2.170(4) Å with a bite-angle (N2-Re1-N1) of 74.95(16)°,
while the rhenium to bromido bond distance was 2.6126(15) Å. The rhenium to
carbonyl carbon bond distances range from 1.912(6) Å to 2.008(7) Å. A distortion of
the octahedral sphere is confirmed by the angles N1-Re1-Br1, N2-Re1-Br1, and C1-
Re1-Br1 which are 85.66(11)°, 83.50(11)° and 176.16(15)° respectively. A dihedral
angle of 7.028(15)° was reported between the equatorial plane and the plane through
the 2,2’-bipyridine system. A hydrogen bonding interaction is observed between H6
and Br1, while three π-interactions are observed in fac-[Re(CO)3(bpy)(Br)].
The photoluminescent properties of eleven rhenium(I) compounds were determined
and emission wavelengths ranging from 604 to 650 nm were found for Re(I)
tricarbonyl complexes and 610 to 670 nm in Re(I) dicarbonyl complexes. The highest emission wavelength was obtained from the water soluble complex
cis-trans-[Re(CO)2(bpy)(PTA)2][NO3] in CH3OH solution. This emission was
significantly higher than the same complex in aqueous solution, which displayed an
emission wavelength of 642 nm. A second water soluble complex,
fac-[Re(CO)3(bpy)(PTA)][NO3], was studied in both CH3OH and aqueous solution.
This compound showed a similar trend to cis-trans-[Re(CO)2(bpy)(PTA)2][NO3],
namely that the emission of these water soluble complexes is higher in CH3OH than
in aqueous solution.Central Research Fund (CRF) of the University of the Free Stat
Deterministic and stochastic analysis of groundwater in unconfined aquifer model
No full textIn several developed countries, groundwater has been recognised as one of the most important natural source of fresh water. It can now be understood why many researchers from all corners from applied science have devoted their attention in developing new methods, models that could be used to monitor and understand the movement of this water within subsurface. The literature nowadays revealed different type of geological formations, including confined, leaky and unconfined aquifers. The movement of water within these three aquifers cannot be captured using the same mathematical models. The Theis model was introduced to capture flow within a confined aquifer, while the Hantush model was suggested to predict the flow within leaky aquifer, these two partial differential equations cannot account for the flow within an unconfined aquifer, and more precisely they are linear equations. To capture flow within an unconfined aquifer, a new mathematical equation was suggested and happens to be integro-differential type. The study of this model is not popular maybe due to the complexity of the mathematical setting. In this dissertation, we considered the model of groundwater flowing within an unconfined aquifer. We derived the conditions under which the exact solution can be obtained. We suggested numerical solutions using different schemes including forward Euler, Crank-Nicholson and Atangana-Batogna schemes. For each of them, we presented detailed study underpinning the stability of the used scheme. To conclude, we suggested a new numerical scheme that combines the fundamental theorem of calculus, Adams-Bashforth and the trapezoidal rule. The method is a new door for investigation in the field of modelling as it is highly accurate and efficient. In addition to this, we argued that differential equations with constant coefficient cannot capture complexities with statistical setting, to solve this problem in case; we converted all parameters included in our equation into distribution functions. The new model was also solved numerically. Lastly, we present numerical simulations from a software package called MATLAB, using normal and statistical data.National Research Foundation (NRF)University of the Free Stat
The politics of narrating the performance of power in selected Zimbabwean autobiographical writings
Get PDFOver the past six decades, Zimbabwean politics and its trajectories have evolved as a result of nationalism, ethnocentrism, decolonisation, neo-colonialism, neoliberalism, nativism, Afro- radicalism and globalisation. These discourses have made Zimbabwean political actors and their supporters pit against each other on grounds of patriotism, race, gender, political affiliation, ethnicity and hegemonic struggles. Furthermore, this study analyses how these varying positions spurred the (dis)continuities between patriotic and ‘oppositional’ narratives in postcolonial Zimbabwe (specifically post-2000). It is important to explore how the schema of inclusion and exclusion manifest themselves in competing autobiographical narratives within the nation’s complex and contested political space. This dissertation analyses the politics of narrating the self, performativity and power in the autobiographical works of Tsvangirai, Msipa and Coltart. The primary concern of this study is to juxtapose these narratives and highlight salient connections between self and nation, past and the present and, autobiography and postcolonial theory. Reading these political autobiographies side by side locates the self in historical and aesthetic contexts that illustrate the faultlines of representation and identity. The study mainly refers to postcolonial theories by Bhabha (hybridity, liminality and mimicry) and Mbembe’s (African modes of writing the self) which interrogate the designation and discrimination of identities and the innovative sites of collaboration and contestation. The study also invokes Smith and Watson’s (2001) delineation of autobiographical modes of narration and McAdams’ (2006, 2008, 2012, 2013, 2018) psycho-literary approaches to personal narratives to critically interrogate narrative identity, life-transitions and imaginative acts of writing the self. Such an eclectic approach dispels illusions, self-justifications, myths and subjective generalisations of historical events and performances. A key finding of this study is that postcolonial politics in Zimbabwe is circumscribed and constituted by metaphors of hybridity, mimicry, liminality and new modes of writing. This dissertation concludes that ‘oppositional’ narratives appropriate and emulate the Zimbabwe African National Union-Patriotic Front’s (ZANU-PF) performance of power to the extent of being travesty of democracy. I also suggest that a revisionist and inclusive writing of the nation goes against the grain of discriminatory and demonisation discourses that foreclose the imagination of having a future President from a minority tribe, race, younger generation, feminine gender and opposition party