Philanthropy of Community in Zimbabwe: Past, Present and Future

The paper presents research findings on philanthropy of community among low wealth groups in rural and urban Zimbabwe and its relevance for development

Synthesis and functionality of boron-, nitrogen- and oxygen-doped shaped carbon-based nanomaterials and titania nanocomposites in electrochemical capacitors

Doctor of Philosophy in Higher Education. University of KwaZulu-Natal,Westville,2020Energy is a global fundamental sector and major concerns are inclusive of; making renewable power economical, reliable and accessible to all, maintain and improve power quality, voltage and frequency, amongst others. There is need for development of intelligent energy storage systems (ESS) that maximise and provides durable storage of electrical power generated. This is a suitable approach towards reducing gas emissions, lowering electricity bills, meet power needs at any time and for lowering excess power fluctuations. Much advancement is required on ESS to shift their optimum working regions towards preferred limits with both high justifiable power and energy. Advancement of ESS need to be sought through developing effective electrode materials. Shaped carbon nanomaterials (SCNMs) are suitable for ESS in the Smart Grids with potential better cost effective and scalable standards. The investigation of related physicochemical properties of SCNMs, modification of nano-structural parameters and development of appropriate strategies that would enhance their functionality in ESS is key in this regard. In this study, various ESS were reviewed with more focus on development of electrochemical capacitors (ECs) with a bias towards the use of SCNMs as electrodes. The work was aimed at understanding the influence of reagent ratio in the physicochemical properties of N-doped multiwalled carbon nanotubes (N-MWCNTs) and graphene oxide (GO). Also, it focused on modifying the functionality of MWCNTs, N-MWCNTs and reduced graphene oxide (RGO) in ECs via introduction and control of heteroatoms such as nitrogen and its functional moieties or introduction of oxygen-containing groups. Thirdly, the work investigated the effect of composite synthesis on the performances of individual components via control of wt.% ratios. Characterisation techniques used include transmission and scanning electron microscopies, atomic force microscopy, textural characteristics, thermogravimetric analysis, elemental analysis, cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, ultraviolet-visible spectrophotometry, Raman and Fourier transform infra-red spectroscopies. N-MWCNTs were synthesized from N,N’-dimethyl formamide and acetonitrile as sp3 and sp hybridized nitrogen sources, respectively, as materials for ECs. The combination of ferrocene carboxaldehyde, N,N’-dimethyl formamide and acetonitrile in N-MWCNTs synthesis was a novel approach. Mixing the sp3 and sp sources in 1:3 ratio enhanced nitrogen content to 9.38% from that of both sp3 (5.87%) and sp (3.49%). The physical properties such as number of concentric shells were tailored by varying synthesis temperature. Pyrrolic N-doping was achieved as the main constituent of nitrogen moieties. Furthermore, GO was synthesized as a preliminary step for further N-doping. The effect of graphite: Na2NO4 reagent ratio in the synthesis of GO was studied to elucidate the influence of the initial step in GO synthesis, via modified Hummer’s method, and to develop novel strategies towards controllable products. The physicochemical properties such as content of oxygen-containing groups on GO and the surface areas were increased from 0% and 2 m2 g-1 to 30% and 188 m2 g-1, respectively, by increasing the proportion of Na2NO4 in reagents. The manipulation of the initial step was a novel means of tailoring the associated physicochemical properties of GO. Also, this study determined, for the first time, the most effective group one sulfate electrolyte at fixed concentrations. This aided the selection of the electrolyte used in the application of the SCNMs in this thesis. Oxygen moieties were introduced, by ultra-sonic waterbath treatment, onto MWCNT surfaces using various reagents namely; HCl, HNO3, H2O2 and HNO3/ HCl solutions. The study highlighted how the various reagents, commonly used to purify MWCNTs after synthesis, modify associated physicochemical properties and alter charge storage characteristics. Oxygen-containing groups increased capacitance of pristine MWCNTs and introduced pseudo charge storage mechanism via oxygen functionalities. HNO3 treated MWCNTs had a 77- and 2.5-fold upgrading from pristine using Li2SO4 and Na2SO4, respectively, whilst HNO3/ HCl was the best, 5 times better, in K2SO4. The oxygen-modified MWCNTs performance was highest and of best quality in Na2SO4. The effectiveness of common GO reductants, namely; ascorbic acid, hydrazine hydrate and sodium borohydride were practically investigated. This was done to select a reductant for the current work. This study also provided a viable novel chemical tuning approach for nitrogen moieties and content as well as to introduce boron, with sodium borohydride. Thirdly, under this particular study, the effect of heteroatoms, boron and nitrogen, as well as nitrogen moieties on physicochemical characteristics of RGO was also explored. Hydrazine hydrate was the most effective reductant and was associated with highest surface area and N-content of 390.55 m2 g-1 and 4.07 at.%, respectively. The nitrogen groups of RGO reduced by means of ascorbic acid, hydrazine hydrate and pristine were pyrrolic, pyridinic and sp3 N-C, respectively. N- doped RGO, particularly pyrrolic moieties, were 76-fold better than B-doped. A further iii iv thermal reduction, of RGO from hydrazine hydrate, increased surface area from c.a. 391 to c.a. 600 m2 g-1 at 750 ℃. The effect of oxygen-containing groups was then investigated in composites of titania with GO, RGO and cellulose reduced graphene oxide (CRG). The wt.% ratios of titania were varied; i.e., 5, 10, 20 and 40%. Based on earlier deductions in this thesis, reductant chosen was hydrazine hydrate. Titania enabled better exfoliation of GO but at higher wt.%, it culminated in larger agglomerates which in turn increased diffusion path-length. RGOTi at 5 wt.% titania increased surface area from 136.89 to 434.24 m2 g-1. The study generally showed that capacitance was better at lower wt.% titania in RGOTi and that cellulose surface area increase was outweighed by associated insulating effect. The present data infers that the impact of oxygen moieties on capacitance of SCNMs was subject to specific structures; MWCNTs, GO and RGO. Capacitance of titania and GO were improved by composite synthesis. Graphenated N-MWCNTs were targeted, as a means, to lessen agglomeration, without the use of surfactants, and to generate 3-D scaffolds for better electrical conductivity channels. Also, better physicochemical characteristics for higher capacitance were obtained via sol-gel than CVD method. The ratios of sp3- and sp-hybridized nitrogen in reagent mixtures, in this thesis, was effectively used to tune the composition of pyrrolic nitrogen moieties. Pyrrolic composition of N-MWCNTs was uniquely aimed because studies of typical moieties on RGO deduced pyrrolic to be better than pyridinic groups. The increase of pyrrolic nitrogen composition; 35, 45 and 60%, culminated in capacitance deterioration. Composite synthesis reduced Warbug length and amplified associated capacitance. The physicochemical properties of RGO, GO, MWCNTs and N-MWCNTs were positively tuned from reagent ratios, conditions and composite syntheses. The conjectured strategies could modulate their overall capacitance via manipulation of heteroatom content and functional groups, amongst others listed herein. Several traits that linked physicochemical properties and capacitance were successfully elucidated. This affirms the hypothesized potential of SCNMs in ESS through understanding and control of both nano-structural parameters and physicochemical properties

COMMUNITY BASED GAME RANCHING AND POLITICS IN CHIRIWO WARD OF MBIRE DISTRICT, ZIMBABWE

N° ISBN - 978-2-7380-1284-5International audienceCommunity based wildlife management in Zimbabwe is rooted in ideas of global significance whose central premise is that local communities will manage natural resources sustainably when rights and responsibilities are devolved to them; benefits of management exceed costs; they capture benefits; and they are small enough in membership to enforce group rules. Using results of research conducted in Chiriwo Ward, Mbire district, this paper revisits these core principles. Six years after CIRAD handed over Chivaraidze Game Ranch to the community, the project is revealing a schism between the aforesaid principles and actual practice. First, the ideal of devolving authority over wildlife to the community has come up against powerful local sectional interests. Second, the ideal of benefits of management exceeding costs is being contradicted by the reality of costs exceeding benefits. Third, the ideal of the community capturing benefits is being negated by the reality of elite capture of benefits. Fourth, the ideal of community cohesion is being neutralised by local leaders' divisive use of kinship and party political ties to gain access to and control the ranch and its wildlife. On the basis of comparative literature and our own findings, we argue for the necessity to investigate and analyse the politics behind project appropriation at the local level. We conclude that building community collective action in wildlife management requires scrutiny and understanding of power politics which shapes local participation and structures the outcomes of wildlife management

Multiwalled Carbon Nanotube-titania Nanocomposites: Understanding Nano-Structural Parameters and Functionality in Dye-sensitized Solar Cells

Nanocomposites consisting of multiwalled carbon nanotubes and titania were synthesized by two methods, namely, sol-gel and chemical vapour deposition (CVD) methods. The work takes advantage of the bridging ability of nanotechnology between macromolecules and the solid state process in engineering alternative nanomaterials for various applications including solar cell fabrication. Physical and chemical characterization of the mesoporous nanocomposites from the two synthetic methods were investigated using Raman spectroscopy, thermogravimetric analysis, Fourier transformation infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, surface characterization and X-ray diffraction analysis. Physicochemical properties in the nanocomposites such as thermal stability, pore volume, crystallinity and surface area were observed to be a subject of MWCNT: titania ratios and synthetic methods. From the CVD synthetic method, observed attributes includemore uniformand smoother coating; better crystallinity and larger pore width than sol-gel method. On the other hand, nanocomposites from sol-gel synthetic method had larger surface areas, were more defective and less thermally stable than those from CVD. Nanocomposites by the CVD method performed 39.2% more efficient than those from sol-gel in light-harvesting experiments. The study shows that the nanocomposites synthesized were more effective than titania alone when the cheaper natural dye, Eosin B, was used. This highlights the great potential of typical nanomaterials in improving the performances of titania in DSSCs as well as lowering the cost of the ultimate devices.KEYWORDS Dye-sensitized solar cells, multiwalled carbon nanotubes, nanocomposite, titania, sol-gel, chemical vapour deposition

The physicochemical properties of carbon nanotube-titania nanocomposite for light harvesting.

M. Sc. University of KwaZulu-Natal, Durban 2014.Nanocomposites for dye-sensitised solar cells (DSSCs) were synthesised from ultrasonic acid-treated multiwalled carbon nanotubes (MWCNTs) and titania precursors by means of sol-gel and chemical vapour deposition (CVD) processes. The wt.% of MWCNTs in nanocomposites were varied from 2 to 98. Physicochemical properties investigation forms the core of the study. Hence, nanocomposites were thoroughly characterised by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), electron dispersive X-ray spectroscopy (EDX), Raman spectroscopy, Fourier transformation infra-red spectroscopy (FTIR), textural characteristics, inductively coupled plasma optical emission spectroscopy (ICP-OES), photoluminescence (PL) and powder X-ray diffraction (XRD) techniques. Nanocomposites were used as photoanode in assembled DSSCs. The gel electrolyte was polyvinyl acetate (PVAc) doped with LiI. Aluminium was the photocathode. The DSSCs were tested for their performance by illuminating them in a solar simulator device. Characteristic hollow MWCNTs morphology with titania particulates was obtained. Both synthetic methods coated small diameter MWCNTs well. EDX spectra showed titania and carbon peaks. The ICP-OES data correlated with TGA in that residual wt.% values were within the expected ranges. Defects from acid treatment lowered thermal stability of pristine MWCNTs from 640 °C to 625 °C. Ti-O-C bond (ca. 1110 cmˉ¹) and anatase form of titania (ca. 669, 577 and 411 cmˉ¹) were observed. Raman spectroscopy showed Eg, A₁g + B₁g₍₂₎ and B₁g₍₂₎ modes of anatase titania at ca. 630, 514 and 396 cmˉ¹ respectively. ID/IG trends indicate that titania reduced defects in MWCNTs. MWCNTs in nanocomposites from the CVD method had fewer defects, highly thermally stable and more uniformly coated, more crystalline, more porous and had smaller surface areas than sol-gel prepared nanocomposites. Nanocomposites had lower eˉ/h⁺ recombination and band gap energy than titania. The optimum MWCNTs wt.% in DSSCs was 15% and CVD nanocomposites were 900% more efficient. From this work, ideal nanocomposites physicochemical properties for DSSCs application include uniform morphology, a defect-free nature, crystallinity, large pore size and volume, and existence of chemical bonds between components. Other factors rather than band gap engineering such as absorption properties of DSSC components also affect DSSC capabilities. Also, the high eˉ conductivity nature of MWCNTs interferes with eˉ transport from the nanocomposites to the counter electrode at high MWCNTs wt.%

Risk Governance in Non-financial Companies

Following the recent financial crisis, risk governance has been brought to the forefront as a prevalent issue in both financial and large complex non-financial companies. This research project takes the form of a cross-sectional study and aims to further understand this issue by investigating the determinates of risk governance mechanisms and reporting structures in large, listed non-financial companies that are listed on the London Stock Exchange’s FTSE100 index. Initially, thematic content analysis was performed to collect data from the company annual reports. Focusing on the 2012 operating period, an index was created to assess the level of risk governance mechanism adoption across the firms. The index consisted of nine variables of risk governance mechanisms, which included the presence of a group level risk role and risk committee, they served to provide an indication of the presence of risk governance within the firms being studied. The research project adopted a mixed methods methodology which included both qualitative and quantitative research methods. Based on a set of 17 independent variables, the determinants of risk governance adoption were investigated. Regression analysis was then performed and only two of the variables, liquidity ratio and debt ratio were found to be statistically relevant determinants. Out of five developed hypothesises, hypothesis 1, which states that there is a positive relationship between financial characteristics and risk governance mechanisms, was proven to be correct. This suggests that financial characteristics are a determinant of the adoption of risk governance mechanisms within large non-financial firms