Synthesis and structural studies of NiS and PdS nanoparticles/nanocomposites from dithiocarbamates single source precursors
- Authors: Nqombolo, Azile
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11359 , http://hdl.handle.net/10353/d1021326
- Description: The main aim of this research is to synthesize Ni(II) and Pd(II) dithiocarbamate complexes and use them as single source precursors for the synthesis of NiS and PdS nanoparticles and metal sulphides potato starch nanocomposites. Four dithiocarbamate ligands were synthesized and characterized using elemental analysis and spectroscopic techniques. The ligands were used to prepared homoleptic Ni(II) and Pd(II) complexes of the dithiocarbamate ligands. The metal complexes were characterized with elemental analysis, UV-Vis, FTIR and 1H-NMR spectroscopic techniques. Conductivity measurements indicate that all the complexes are non-electrolytes in solution and results from the electronic spectra studies confirmed the proposed 4-coordinate square planar geometry around the metal ions. The nickel complexes showed d-d transitions around 477 nm while in the palladium complexes, no d-d transitions were observed but the compounds showed strong metal to ligand charge transfer transitions. From the FTIR spectra studies, it can be confirmed that the complexes were successfully synthesised because all peaks of interest were observed at expected regions from the literature. The νC-N was observed around 1469-1495 cm-1, νC=S around 1101-1188 cm-1 and νC-S around 738-1060 cm-1 for both Ni(II) and Pd(II) complexes. νNi-S was observed around 375-543 cm-1 and νPd-S around 529-545 cm-1. The FTIR also confirmed that the dithiocarbamate ligands act as bidentate chelating ligands through the sulfur atoms. The complexes were used as single source precursors and thermolysed in hexadecylamine (HDA) at 220 °C to prepare four HDA-capped nickel sulfide nanoparticles and four palladium sulfide nanoparticles. The as-prepared nanoparticles were studied with optical absorption spectra, photoluminescence, powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The optical studies results showed that NiS have large band gaps that are greater than that of the bulk, therefore they are found to be blue shifted relative to the bulk, which shows that they have small particle size and thus confirming their quantum confinement effect. PL spectra reveal that the emission peaks are red shifted compared to the absorption band edges of the nanoparticles. The XRD patterns confirmed the formation of cubic and rhombohedral phase for NiS nanoparticles and cubic phase for PdS nanoparticles. SEM images of both NiS and PdS show uniform surface morphology at low and high magnification with different shapes. EDS analyses confirmed the presence of Ni, S, and Pd in each of the spectrum indicating that the nanoparticles were successfully synthesized. TEM images showed that the synthesised nanoparticles have uniform and narrow size distribution with no agglomeration. The sizes of the NiS nanoparticles were found to be in the range of 12-38 nm for NiS1, 8-11 nm for NiS2, 9-16 nm for NiS3 and 4-9 nm for NiS4. The TEM images for the as-prepared PdS nanoparticles showed that the average crystallite sizes are 6.94-9.62 nm for PdS1, 8-11 nm for PdS2, 9-16 nm for PdS3 and 4-9 nm for PdS4 respectively. The nanoparticles were used to prepare potato starch nanocomposites and SEM images indicate that the surface morphology of starch polymer nanocomposites compose of potato starch and few particles in between the pores of the matrix, this is due to the small ratio of nanoparticles used.
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- Date Issued: 2016
Technical and institutional constraints faced by vegetable co-operatives in the Buffalo City Metropolitan Municipality in Eastern Cape Province, South Africa
- Authors: Madlodlo, Sinazo
- Date: 2016
- Subjects: Agriculture, Cooperative -- South Africa -- Eastern Cape , Vegetable trade -- South Africa -- Eastern Cape , Cooperative marketing of farm produce -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1497 , vital:27396
- Description: This study focused on the technical and institutional constraints faced by the vegetable co-operatives with regard to the impact on productivity. Vegetable co-operatives have no access to markets due to their poor performance on productivity and poor quality produce resulting to low prices for the produce such that they cannot compete in a market economy. In this study, the data was drawn from a sample of thirty vegetable co-operatives in the Buffalo City Metropolitan Municipality (BCMM) of the Eastern Cape; obtained through focus group discussions and interviews from each cooperative. The objectives of the study are to measure the productivity of vegetable co-operatives using Total factor productivity analysis (TFP) and profitability of vegetable co-operative using Gross Margin (GM). Followed by the descriptive statistics in identifying and assessing the socio-economic characteristics as well as coping strategies adopted by vegetable co-operatives in BCMM where percentages, means and tables are used looking at the highest frequency. The results show that the vegetable co-operatives in the BCMM are not productive and profitable due to major constraints experienced by co-operatives such as lack of market, information, trainings and business skills, capital, infrastructural facilities, effective extension services that all leads to poor produce quality. Co-operative is said to be profitable and viable if total revenue is greater than the total variable cost which makes the gross margin positive. In this case, the total gross margin is negative. The results showed that the production costs, maintenance (tractor hire, generator hire and servicing) and electricity costs were the major costs incurred in the production of vegetable by the co-operatives.
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- Date Issued: 2016
The biomass production, nutrient content and silage quality of Perennial ryegrass (Lolium perenne (L)) Cocksfoot (Dactylis glomerata (L)) and Tall fescue (Festuca arundinacea (Schreb)) varieties grown under irrigation in Alice, South Africa
- Authors: Tikwayo, Sizwe Edward
- Date: 2016
- Subjects: Ryegrasses -- Varieties -- South Africa -- Eastern Cape Ryegrasses -- Irrigation -- South Africa -- Eastern Cape Biomass energy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1796 , vital:27560
- Description: The study aims to evaluate the biomass production and nutrient content and silage quality of perennial ryegrass (Lolium perenne (L)), cocksfoot (Dactylis glomerata (L)) and tall fescue (Festuca arundinacea (Schreb)). Six varieties were used, two for each species. A completely randomized block designed replicated three times was conducted at University of Fort Hare Research Farm during 2014-2015 growing season. The plots were harvested at four-week interval (post emergency) for one year. Biomass yields were measured for fresh forage and dry matter yield. Duplicated samples were then dried, milled and analyzed for chemical and mineral composition (CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe) for only winter season. In addition the grasses were ensiled and the silage was analyzed for its fermentation parameters and nutrient content (lactic acid, pH, DM, CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe). Biomass results showed significant differences (P < 0.05) between season and varieties. On average Tall fescue varieties Jessup (13741.67 FM kg/ha), Alix (12007.78 FM kg/ ha) and Ryegrass varieties Samson (11597.22 FM kg/ha) and Nui (10591.67 FM kg/ha) had the highest fresh biomass yield. Similarly, Tall fescue varieties Jessup (2833.06 DM kg/ha) and Alix (2708.3 DM kg/ ha) and Ryegrass varieties Samson (2169.44 DM kg/ha) and Nui (2169.67 kg/ha) had the highest dry biomass yield. Throughout the year the average biomass yield was significantly different among species (P< 0.05). During summer and autumn Tall fescue varieties Jessup and Alix gave the highest dry matter yields of 3855.5 to 1977.8 DM kg/ha, and 3877.8 to 1900 DM kg/ha, respectively, and followed by Cocksfoot 2400 DM kg/ha. Ryegrass had the highest dry matter biomass yield in winter (2975 DM kg/ha) and the least in summer (977.75 DM kg/ha). There were no significant (P>0.05) differences on the chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe) of the six varieties. The grass silage results showed significant differences (P< 0.05) among the six varieties for moisture content. Perennial ryegrass variety Nui (66.76 percent) had low moisture content than the other grass silages. The different varieties had no significant effects (P>0.05) on chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe). It is concluded that the biomass production of the six varieties of three grass species was different throughout the year under irrigation hence Ryegrass and Tall fescue are recommended for dairy farmers in the region for all seasons. It can be concluded that there is no difference with respect to fermentation characteristics and nutrient content among the varieties of the grass species.
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- Date Issued: 2016
The classsification of fuzzy subgroups of some finite Abelian p-groups of rank 3
- Authors: Appiah, Isaac Kwadwo
- Date: 2016
- Subjects: Fuzzy sets Abelian groups Finite groups
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2468 , vital:27845
- Description: An important trend in fuzzy group theory in recent years has been the notion of classification of fuzzy subgroups using a suitable equivalence relation. In this dissertation, we have successfully used the natural equivalence relation defined by Murali and Makamba in [81] and a natural fuzzy isomorphism to classify fuzzy subgroups of some finite abelian p-groups of rank three of the form Zpn + Zp + Zp for any fixed prime integer p and any positive integer n. This was achieved through the usage of a suitable technique of enumerating distinct fuzzy subgroups and non-isomorphic fuzzy subgroups of G. We commence by giving a brief discussion on the theory of fuzzy sets and fuzzy subgroups from the perspective of group theory through to the theory of sets, leading us to establish a linkage among these theories. We have also shown in this dissertation that the converse of theorem 3.1 proposed by Das in [24] is incorrect by giving a counter example and restate the theorem. We have then reviewed and enriched the study conducted by Ngcibi in [94] by characterising the non-isomorphic fuzzy subgroups in that study. We have also developed a formula to compute the crisp subgroups of the under-studied group and provide its proof. Furthermore, we have compared the equivalence relation under which the classification problem is based with various versions of equivalence studied in the literature. We managed to use this counting technique to obtain explicit formulae for the number of maximal chains, distinct fuzzy subgroups, non-isomorphic maximal chains and non-isomorphic fuzzy subgroups of these groups and their proofs are provided.
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- Date Issued: 2016
The perceptions of nurse educators regarding the use of high-fidelity simulation in nursing education at a South African private nursing college
- Authors: Janse van Vuuren, S V
- Date: 2016
- Subjects: Nursing -- Study and teaching -- Simulation methods Simulated patients
- Language: English
- Type: Thesis , Masters , MCur
- Identifier: http://hdl.handle.net/10353/1752 , vital:27555
- Description: Although Nurse Educators are aware of the advantages of simulation-based training, some still feel uncomfortable to use technology or lack the motivation to learn how to use the technology. The aging population of nurse educators cause frustration and anxiety. They struggle with how to include these tools, particularly in the light of faculty shortages. Nursing education programmes are increasingly adopting simulation in both undergraduate and graduate curricula. Scoping literature reviews show that nursing practice has changed in recent years, placing demands on nurse educators to utilise different approaches in education. The fact that nurse educators are an aging population needs to be taken into consideration and acknowledge that many of them did not grow up with computers and lag behind in technological skills. The aim of this study was to investigate the perceptions of nurse educators regarding the use of high-fidelity simulation in nursing education at a South African Private Nursing College in order to be able to determine why High-fidelity Simulators (HFS) have not yet been embraced by nurse educators and students. A national survey of nurse educators and clinical training specialists was completed with 128 participants; but only 79 completed the survey. In addition to background information, participants were questioned about their use of simulators. They were asked to complete the Technology Readiness Index. Information was also obtained regarding their perceptions of the use of HFS. Findings included indications that everyone is at the same level as far as technology readiness is concerned; this, however, does not play a large role in the use of HFS. This finding supports the educators’ need for training to adequately prepare them to use simulation equipment. Recommendations for further study include research to determine what other factors play a role in the use of HFS, studies to determine whether the benefits of HFS are superior to other teaching strategies warranting the time and financial commitment. The results of this study can be used as guidelines for other institutions to prepare their teaching staff for the use of HFS.
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- Date Issued: 2016