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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Sorption and solubility of a denture base acrylic

Latief, Abduraghman January 2012 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Dental Technology in the Faculty of Health and Wellness Sciences at the Cape Peninsula University of Technology, 2012 / Statement of problem It is well documented that water sorption and water solubility by auto-polymerizing resins have a negative impact on their physical properties and may lead to harmful tissue reactions. The presence of residual monomer is often identified as the main cause for adverse tissue reactions. To optimize the polymerization reaction, the use of the proper powder/liquid ratio is recommended in the fabrication of a dental appliance. It is also recommended that a dental appliance should be soaked in water for at least 24 hours before delivery to a patient, in order to reduce the possible adverse effect. For auto-polymerizing resins, associated with higher residual monomer levels than heat-cured resins, soaking the appliance at elevated temperatures (65ºC for 60 minutes), would reduce the residual monomer content more efficiently than at room temperature. This requires additional processing conditions from the technician or dentist. Changing the powder/liquid ratios, deliberately or not, may modify the residual monomer content of the final product. A relationship exists between the levels of residual monomer and water sorption. Also, residual monomer leaching into the oral fluids may lead to adverse effects such as, oral tissue irritation or a delayed hypersensitivity reaction. Aim of the study The aim of this study was to evaluate the effect of different powder/liquid ratios and different water temperatures on the levels of sorption and solubility of an auto-polymerizing resin material used for denture bases. The null-hypothesis tested was that there is no difference in sorption and solubility among groups of specimens made from an auto-polymerizing resin material soaked in water at different temperatures and/or fabricated with different powder/liquid ratios. Material and methods Specimens were made from cold-cure pour-type denture base resin (Type 2, Class 2) using different powder/liquid ratios and soaked at different soaking temperatures. One group of specimens fabricated with the manufacturer’s recommended powder/liquid ratio and soaked in water at 37ºC, served as the control group for both experiments. Custom-made stainless steel moulds were used to fabricate resin disks, with a diameter of 50mm and a thickness of 0.5mm. For the temperature-controlled experiment, identical specimens were prepared and stored in distilled water at 37ºC; 45ºC; 55ºC and 67ºC. For the ratio-controlled experiment, the ratios were increased incrementally for each group, starting with a 10% increase, followed by a 15%; 20% and 25% increase in monomer. Water sorption and solubility were tested in accordance with ISO Standard 1567 (1999). Specimens were weighed before and after water immersion, and desiccation. Water sorption and solubility were calculated using the difference in wet and dry mass and the volume of the specimens. The water sorption and solubility results were analyzed by means of analysis of variance. For multiple comparisons, Bonferroni simultaneous confidence intervals (α=0.05) were applied. Results For the ratio-controlled experiment, water sorption mean values varied from 24.148 μg/mm3 to 25.1333 μg/mm3. Statistically significant differences in mean values were found between the following groups: 0%-10%; 0%-15%; 0%-25%; 10%-20%; 15%-20% and 20%-25% ratio groups (P<.0001). Water solubility mean values varied from 0.616μg/mm3 to 0.932μg/mm3. Statistically significant differences in mean values were found between the following groups: 0%-15%; 0%-20%; 0%-25% and 10%-25% and 20%-25% ratio groups (P<.0001). For the temperature-controlled experiment, water sorption mean values varied from 24.185μg/mm3 to 26.434μg/mm3. Statistically significant differences in mean values were found between the following groups: 37ºC-45ºC; 37ºC-55ºC; 37ºC-67ºC; 45ºC-67ºC and 55ºC-67ºC temperature-controlled experiments (P<.0001). Water solubility mean values, for the same experimental groups, varied from 0.616μg/mm3 to 2.752μg/mm3. Statistically significant differences in mean values were found among all the 6 pairs of groups (P<.0001). Despite statistical differences, the water sorption and water solubility values of the tested resin for both experiments and all groups were within the ISO Standard 1567 (1999) specification limits. Conclusion For the ratio-controlled experiment, there was an inverse relationship between the mean sorption and solubility values with an increase in liquid in the mixture: low water sorption levels are associated with high solubility levels. The lower water sorption and higher solubility results for more fluid mixtures could be related to initial and residual high monomer content characteristic of auto-polymerizing materials. These higher levels of free monomer are consequently released upon immersion in water; hence the higher water solubility levels. For the temperature-controlled experiment, a higher soaking temperature resulted in an increase in water solubility levels. The higher solubility levels could be attributed to the higher soaking temperatures causing higher or faster monomer diffusion from the resin material. Except for the 67ºC group, sorption is also lower with higher temperatures. It may be assumed that an additional polymerization process takes place and a subsequent more inaccessible polymer matrix is produced. For the 67ºC group, thermal expansion may explain the higher sorption level. Clinical Implications In terms of the sorption and solubility results, this auto-polymerizing pour-type resin may be used as a denture base resin. Even though statistical differences were demonstrated, the material satisfies the ISO 1567 (1999) requirements not only for auto-polymerizing but also for heat-polymerizing resins. Therefore, within limits, the mixture may be prepared more fluidly in order to improve flow of the material, without negatively affecting its sorption and solubility properties. Because solubility is higher at higher soaking temperatures, this property can be used to minimize monomer content of the appliance. Therefore, it is recommended that the dental appliance be soaked in warm water, below 67ºC, prior to delivery to the patient.
22

Reference values for thyroid uptake of technetium-99m pertechnetate for the Namibian population

Hamunyela, Roswita Hambeleleni January 2012 (has links)
Dissertation submitted in fulfilment of the requirements for the degree Master of Technology: Radiography (Nuclear Medicine) In the Faculty of Health and Wellness Sciences At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2012 / Thyroid physiology and structure can be evaluated by scintigraphic imaging. Iodine-131, discovered in the late thirties was the first radioisotope to be used for thyroid uptake assessment, since then thyroid uptake and imaging continues to play a vital role in different thyroid related clinical situations. Because Iodine-131 has serious disadvantages related to high radiation dose, it has been limited to staging and follow up of patients with thyroid carcinomas. Its substitute Iodine -123 has proved to be suitable in terms of shorter half-life and better imaging energy. Technetium-99m pertechnetate, because of its availability is also used for thyroid imaging and uptake assessment. The similarity of the Technetium-99m pertechnetate ions and iodide is the explanation for the thyroid glands ability to absorb it. Historically, chronological changes in the normal values of thyroid uptake normal values have been reported in different geographical areas. These changes have been linked to geographical and chronological fluctuations in dietary iodine intake in different populations. Technetium-99m pertechnetate, Iodine-131 and Iodine-123, all reflect thyroid iodide accumulation. In areas where there is iodine deprivation there will be elevated radioisotope uptake in euthyroid persons, and radiotracer uptake is even higher in areas of Iodine deficiency. Conversely in areas where a population is exposed to stable iodine and abundant amount of iodine intake from other sources, radiotracer uptake will be decreased. Namibia is a country with mixed ethnicity consisting mainly of Africans (Hereros, Ovahimba, Kavangos, Caprivians, Ovambo, Damaras, Namas, Bushmen, Coloureds and Caucasians). The population has access to dietary iodine and all ethnic groups consume reasonable amounts of food containing iodine such as bread, dairy products, table salt and sea food. Similar to other Nuclear Medicine departments worldwide, Namibia makes use of Technetium-99m pertechnetate for thyroid uptake and imaging. However thyroid uptake quantification needs to be related to normal values as a point of reference. Despite reports of thyroid uptake fluctuations of normal values and reports emphasising the importance of periodic checks on the thyroid uptake normal values, Namibia has never determined these reference values. This study examines the fundamental statement posed in the hypothesis that the thyroid uptake reference values for Technetium-99m pertechnetate in a Namibian population deviate from available International normal reference values. Eighty three participants considered to be euthyroid from Windhoek, Namibia received Technetium-99 m pertechnetate as part of their evaluation. The euthyroid state was based on a combined evaluation of clinical history, palpation of the thyroid gland and assessment of thyroid hormones (TSH, T3 and T4). The objectives of the study were:  To establish normal reference values of Technetium-99m pertechnetate uptake in euthyroid persons in Namibia.  To compare the outcome reference values to current available existing International normal reference values.  To determine possible factors contributing to the deviation of thyroid uptake reference values in the Namibian population.  To recommend reference values for Namibia. This was achieved by studying the unmedicated 83 participants with their iodine diet, rather than patients with thyroid or other diseases. The participants reported to the Nuclear Medicine department. The participants completed a questionnaire designed to reveal the presence of thyroid pathologies or any other pathology. The completed questionnaire was reviewed and if the participant fulfilled the requirements for the study, blood was drawn for thyroid hormone assessment. The participants were then given 100MBq Technetium-99m pertechnetate intravenously. Using a low energy high resolution dual head gamma camera, the thyroid uptake was recorded at 20 minutes. There was a marked difference between the International normal values (0.75% to 4%) used in the Nuclear Medicine department and those found in this study. The results of seven subjects were excluded due to abnormal blood results, and technical errors, bringing the actual sample size to 76 euthyroid participants. The age range was 39 to 81 years, and there were 58 females and 18 males. The mean uptake for the euthyroid group was found to be 0.78%± 0.45%. The Kolmogorov-SmirnovaLilliefors Significance parametric test presented us with results that state that our population has a non-normal distribution, and therefore the standard deviation should not be applied to determine the normal values. The statistical test for skewness and kurtosis was adopted in this study to correct for skewness and the normal values determined were 0.35% to 1.22% (95.5% CI) of Technetium-99m pertechnetate at 20 minutes. An alternative method used to determine the normal reference range for Technetium-99m pertechnetate in a study sample obtained from a non- normal distribution was determined using the 5th and the 95th percentiles .The normal reference range using the 5th and the 95th percentile was 0.17% - 1.7%. This study provides new evidence supporting the importance of periodic checks on normal reference values. The evidence is provided by the analysis of the empirical data obtained in this study of a population that has sufficient daily intake of stable iodine. The results obtained from this study and other studies proving the difference in thyroid uptake between different populations and geographical regions makes it incumbent upon laboratories to establish a normal reference range for a particular geographical location. Furthermore the study attests to the importance of re-evaluating normal values for thyroid uptake as part of a quality assurance programme.
23

An evaluation of responsible tourism practices in the Tanzanian tourism industry

Feruzi, Joyce Kokwongeza January 2012 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Tourism and Hospitality Management in the Business Faculty at the Cape Peninsula University of Technology, 2012 / This thesis concerns sustainable tourism development in Tanzania. It determines the extent to which Tanzanian tourism policies have incorporated sustainable frameworks and principles and also ascertains the extent to which tour operators in Tanzania have adopted sustainable tourism practices. Furthermore, it attempts to understand the constraints to tourism development for future successful planning of Tanzania as a favourable tourist destination in Africa. One of the key principles of sustainable tourism is that the local population is placed at the centre of tourism development interventions in terms of participation in decision-making and benefit sharing. Sustainable tourism principles also support that environmental regulations should be at the forefront of tourism’s industry advocates in order to mitigate environmental degradation and deterioration in the form of vegetation degradation, disruption of wildlife behaviour, pollution increase and general over utilisation of resources. However, Tanzanian tourism policies do not incorporate environmental and social concerns adequately, nor do policy makers develop these policies with a unifying strategic vision in mind. A key example is failure of the tourism policy to include consideration of social and cultural factors such as community conservation of natural resources. Tanzania’s tourism sector is growing fast, and its contribution to the economy’s growth is significant. As a result, it has attracted investment and policy initiatives to support its development. Key problem areas that have been identified throughout the thesis are:  Low priority of sustainable policies - the emphasis is still on income generation for government. Sustainable policies are absent in the Integrated Tourism Master Plan (ITMP), Wildlife Policy and Hunting concessions;  Lack of adequate feedback mechanisms;  Apparent clash between sustainable policies and communities that are involved in subsistence farming on communal lands. Changing the system has huge socio- cultural impacts, while government shies away from this;  Low level of community involvement in tourist activities and planning matters;  Inadequate implementation and monitoring of strategies. The researcher, therefore, recommends that tourism planning should not only be a top down approach, but should involve all stakeholders in the tourism industry. Locals should be involved in tourism conservation decision making and the management of tourism policies, and should share in the financial proceeds of tourism. This will increase the level of conservation in tourism, as more people will be informed and be involved. The process of involvement of communities is crucial, as it decreases levels of illegal tourism activities on communal lands. The researcher believes that once locals are engaged in the planning of tourism related ventures, they will make an effort to conserve and preserve resources. Even though tourism policies in Tanzania make a note of sustainable practices (in terms of conservation and community involvement), it has only achieved these objectives on paper, and not enough has been done to ensure that these actions are carried out. It is also evident that development of tourism in Tanzania is a priority, while much focus has been placed on this owing to the economic value that it signifies. The main objective of Tanzania’s tourism policy is to promote low-density, high quality and high-priced tourism. One of the major problems with the government is that their concern for making money outweighs the need to implement sustainable tourism behaviours, therefore, leaving the environment and communities at a disadvantage, which eventually causes problems for destinations and the economy, at large.
24

The impact of a communications intervention on engineering students extended curriculum programme at Cape Peninsula University of Technology

Ogle, Marie-Anne January 2010 (has links)
A Thesis Presented to: The Faculty of Education Cape Peninsula University of Technology by Marie-Anne Ogle in fulfilment of the requirements for the degree of Master of Education Cape Peninsula University of Technology December 2010 / Many students in my Communication Skills class, especially those from rural areas, who had passed their Grade 12 English examination, were unable to express themselves competently, and as a result, they lacked the self-esteem and confidence to express their abilities. It has now been recognised that students are in need of a strong foundation that will bridge the gap from school to university and will allow them to cope with any situation within the workplace. The accent has changed from memorising factual knowledge, to acquiring literacy skills needed in everyday living and the world of work. It has become necessary to find a suitable means of helping these students to cope linguistically. This study uses grounded theory to focus on whether an intervention based on a natural approach to acquiring a language, could improve students’ oral and written skills as well as their confidence. Enthusiasm and the development of a love for language and an ‘I-can-do-it’ attitude were promoted instead of the traditional language exercises. Reading for enjoyment, participation and speaking out were encouraged – all underpinned by respect. The results of an oral presentation, a written essay and an interview with each candidate were analysed at the start of the seven-month intervention programme. A post-test of the three procedures was done to gauge change. An increase in both oral presentation marks and written work was also noted at the end of the intervention period. Themes such as confidence, learning to work with different people and understanding their ideas, an introduction to other cultures, tolerance and respect emerged. All these themes are part of the ‘envisaged learner’ in the Department of Education’s National Curriculum Statement Grades R – 9. The results have guided the development of a prototype intervention, which is central to the concept of self-esteem as a path for future literacy development in school and post-school education. Bolstering this sense of self-esteem is the key to working with new learners of English in the tertiary context.
25

The influence of gangsterism on the morale of educators on the Cape Flats, Western Cape

Dos Reis, Karen Marion January 2007 (has links)
Dissertation submitted in fulfilment of the requirements for the MAGISTER EDUCATIONIS in the Faculty of Education and Social Sciences at the Cape Peninsula University of Technology 2007 / Gangsterism affecting schools on the Cape Flats, as well as concerns about this phenomenon as addressed by the Provincial Minister of Education, Cameron Dugmore, during his Education Budget Speech in 2006, has led to widespread media attention in South Africa. Despite the Western Cape Education Department’s implementation of the Safer Schools project in 2001 to assist educators working in gang-ridden communities, not enough is being done to eradicate the problems caused by gangsterism which educators face in their schools on a daily basis. This research embarks on enquiring how gangsterism influences the morale of educators, focusing specifically on the educators’ perception of their morale and their experiences while working in gang-ridden communities. The research acknowledges that the educators play a vital role in education and are therefore regarded as key stakeholders in a community. The research is located in a qualitative paradigm because it seeks to achieve a deeper understanding of the educators’ morale disposition in gang-ridden communities and investigates the constructs of how gangsterism influences the morale of educators. Data was collected from principals and educators working in the following gangridden communities: Bonteheuwel, Manenberg, Heideveld, Hanover Park and Valhalla Park. A total of 53 respondents, including both educators and principals, participated in this research. Methods of data collection included observations, seven unstructured interviews and six structured focus group interviews. The result revealed that gangsterism does influence the morale of educators working in gang-ridden communities. It was also found that gangsterism affects the whole school community - educators, learners and parents. It is a powerful yet destructive phenomenon and has a negative effect on educator morale.
26

Accumulation and toxicity of metals in oysters (Striostrea margaritacea) from the South African South Coast

Slabber, Michelle Yvonne January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the MTech: Oceanography in the Faculty of Applied Sciences at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2013 / The current status of metal pollution off the South African South coast is not well known. This study was the first to be undertaken in many years using Striostrea margaritacea as a subject species. The aims of the study were to determine the degree of metal contamination in the water, sediments, oyster tissues and oyster shells at sites selected in Witsand, Wilderness and Goukamma, as well as to establish if Striostrea margaritacea qualifies as a successful biomonitor when using lysosomal destabilization as a tool. Seasonal variations between sites were also considered. Other objectives, such as the potential of a Marine Protected Area (MPA) as a control site and the necessity of a monitoring program along the south coast were also included. Sites were sampled seasonally for one year at spring low tides. Ten oysters were collected from each individual site upon each visit. The Neutral Red Retention Time (NRRT) assay was used to determine lysosomal membrane integrity of oyster haemocytes, whereafter oysters were sacrificed for metal analyses. Metals that were analysed are aluminium (Al), copper (Cu), zinc (Zn) and iron (Fe). Metal analyses were done using an Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP- AES). All statistical analyses were performed using ANOVA on Ranks to determine if there were significant differences between sites and between sampling occasions. Aluminium concentrations found in the water column at all sites were considered as low. Iron, zinc and copper concentrations within the water column can on the other hand be considered as high when comparisons are drawn with other studies and data sets. Sediment concentrations for all the metals within the present study were considered to be low when compared to other studies and guidelines. There were not many significant differences recorded between sites and no seasonal patterns were present. Within the tissues of the oysters, the metal ranges are considered to be low when compared to other studies. No definite conclusion about the contamination status of the oyster tissue could be drawn due to the lack of comparative literature. A field study in conjunction with a laboratory experiment should yield more reliable results. There were also no seasonal trends present and very few differences between sites. The bioaccumulation factors were considered as being low with a few exceptions where they were moderate when oyster tissue data was compared to water and sediment data. Concentrations for Al, Zn and Cu in the shells could be considered low when comparisons are drawn, with the exception of Fe that was found to be high. The bioaccumulation factors were considered to be low when oyster shell concentrations were compared to water and sediment data. There were also no seasonal trends present and a prolonged sampling period is suggested to further investigate these findings. When a comparison was drawn between the tissue and shell data a clear pattern was evident. Al and Fe concentrations were highest within the shell where as Zn and Cu concentrations were highest within the tissues of the animal. The theory of mineralization is supported by these findings where bivalves will use their shell as a reservoir for micronutrients and other substances. The NRRT assay revealed that lysosomal membrane destabilization had occurred and that the animals appeared to be stressed for the duration of the sampling period. Site 3, within the MPA, had the longest retention time. The retention times that were recorded were short when compared to other studies. This assay did however show potential as a basic monitoring tool from which more thorough investigations can be initiated. In conclusion, the study sites along the south coast of South Africa does not seem to be contaminated by Al, Zn, Cu or Fe when data is compared to international and local water quality guidelines, sediment quality guidelines and other studies. Also, as concentrations between sites did not differ greatly, it is inconclusive whether or not the MPA can be used as a reliable references site for in situ studies. More vigorous and lengthy studies should be undertaken to contribute to current knowledge of our indigenous species, Striostrea margaritacea and to aid in the development of better management of this resource as well as an ongoing monitoring programme.
27

Structure and reactivity of selected binaphthyl derivatives

Kabwit, Rodriguez Yav January 2013 (has links)
Thesis presented to the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY for the degree of MASTER OF TECHNOLOGY Department of Chemistry, Cape Peninsula University of Technology, Cape Town Campus, Zonnebloem, October 2013 / In this thesis, the complexation behaviour of the host compounds, 1,1’-binaphthyl- 2,2’-dicarboxylic acid (BNDA) and 1,1’-binaphthyl-2,2’-diol (BINOL) were investigated. These hosts are large, bulky and scissor shaped; they contain functionalities to selectively interact with other molecules. A series of small organic compounds, particularly amines, were used in the preparation of the complexes. BNDA formed three complexes with acyclic amines, two complexes with the cyclic amines and two complexes with a racemic amine in different solvents. All the complexes formed were salts. The amines used were diethylamine, di-nbutylamine, cyclohexylamine, dicyclohexylamine, and sec-butylamine. For the studies with the acyclic amines and cyclic amines, crystals were grown in methanol as a co-solvent. Similar experiments were conducted with BINOL. Successful complexation only occurred with cyclohexylamine and dicyclohexylamine respectively. An amine host, 1,1’-binaphthyl-2,2’- diamine (BINDIA) was also considered with acidic and amide guests to extend the study of the binaphthyl derivatives, but from the array of guests used, the host only formed an inclusion compound with dimethylacetamide (DMA). The structures of all the complexes were elucidated using single crystal X-ray diffraction. Thermal analysis was performed in order to determine the thermal stability of the complexes, including techniques such as thermogravimetry, differential scanning calorimetry and hot stage microscopy. The kinetics of desolvation was investigated for some of the complexes.
28

Synergistic effects in clathrate selectivity

Sayed, Amina January 2012 (has links)
Thesis (MTech (Chemistry))-- Cape Peninsula University Technology, 2012 / The inclusion behaviour of a series of hydroxyl hosts with a variety of liquid guests has been investigated. The host 9-(4-methoxyphenyl)-9H-xanthen-9-ol (A1), C20H16O3, forms inclusion compounds with aniline (ANI), 3-picoline (3PIC), morpholine (MORPH), Nmethylacetamide (NMA) and N-methylformamide (NMF). Their structures have been elucidated and correlated with their thermal behaviour. The inclusion compounds A1ANI and A1MORPH were successfully solved in space group P21/c, whereas A13PIC was solved in 𝑃ī. Non-isothermal kinetics of desolvation were performed for A13PIC and A1MORPH. The packing of A13PIC and A1MORPH is characterized by (Host)(Guest) hydrogen bonds, whereas A1ANI is stabilised by (Host)(Host) hydrogen bonding. Three structures were obtained for the host A1 and the guest N-methylacetamide, with structural formulas of C20H16O3 C3H7NO (A1NMA), C20H16O3 2C3H7NO (A12NMA) and 2C20H16O3 2C3H7NO (2A12NMA). The packing of A1NMA, A12NMA and 2A12NMA are characterized by (Host)-OHO-(Guest) and (Guest)-NHO-(Guest) hydrogen bonds, which gave hydrogen bonding patterns of 𝐶2 2(7), 𝐶3 3(11) and 𝐶4 2(11) respectively. The hydrate A1NMFH2O was successfully solved in the triclinic space group 𝑃ī. The A1NMFH2O hydrogen bond pattern may be described according to Etter’s notation as 𝑅4 2(8) and 𝑅6 6(16). The host 9-(3-methoxyphenyl)-9H-xanthen-9-ol (A2), C20H16O3, forms inclusion compounds with morpholine (A2MORPH), N-methylacetamide (A2NMA) and N-methylformamide (A2NMF), with host-guest ratios 1:1. The crystal structure of the apohost was solved in Pbca with Z=8. The structures of A2MORPH and A2NMF were solved in 𝑃ī, whereas A2NMA was solved in P21/n. The packing of these structures is stabilised by (Host)(Guest) hydrogen bonds. The host 5-(4-methoxyphenyl)-5H-dibenzo[a,d]cyclohepten-5-ol (A26), C22H18O2, forms inclusion compounds with aniline (A26ANI) and morpholine (A26MORPH). A26MORPH and A26ANI crystallised in the space groups Pc and 𝑃ī respectively. The packing of these structures are characterized by (Host)-OHO-(Host) hydrogen bonding. A guest exchange reaction was performed. The host compounds 5-(4-chlorophenyl)-5H-dibenzo[a,d]cyclohepten-5-ol (C21H15OCl), 5-[3(trifluoromethyl)phenyl]-5H-dibenzo[a,d]cyclohepten-5-ol (C22H15OF3) and 5-(naphthalen-1-yl)-5H-dibenzo[a,d]cyclohepten-5-ol (C25H18O) form inclusion compounds with morpholine. All three structures were solved in 𝑃ī with the host molecules hydrogen bonded to the morpholine guests.
29

Nickel pollution abatement from landfill leachate using biomaterials

Kakalanga, Sumbu January 2012 (has links)
Thesis submitted in fulfilment of the requirements for the degree of Master of Technology: Chemistry in the Faculty of Applied Sciences at the Cape Peninsula University of Technology, 2012 / Batch experiments were conducted to assess the removal of Ni(II) from aqueous solutions and landfill leachates using low cost adsorbents eggplant peel (EGP), sweet potato peel (SWP) and banana peel (BNP). Preliminary studies were carried out to optimize biosorbent mass, pH, Ni(II) concentration, temperature and contact time for Ni(II) removal. The optimized conditions were then applied to landfill leachates using the selected low cost adsorbents. Ni(II) removal efficiency for each biosorbent was investigated for each parameter. Results indicated that biosorbents masses, pH, initial concentration as well as solution temperature were important factors influencing Ni(II) removal from aqueous solutions. Percentage Ni(II) removal was 66±0.30, 38±3.97 and 33±1.20 using EGP, SWP and BNP, respectively. Ni(II) removal efficiency increased significantly (P ≤ 0.05) with increasing biosorbent mass, pH and Ni(II) initial concentration while it decreased significantly (P ≤ 0.05) with increasing temperature. Although Ni(II) removal efficiency varied significantly with time and the biosorbents no significant (P 0.05) difference was observed between the time interval whether the experiment was conducted in batch or semi batch mode. Results of FTIR studies indicated that several binding and chelating functional groups such as carboxyl, carbonyl and hydroxyl groups on the biomaterials surfaces could be responsible for Ni(II) biosorption. The optimum biosorbent mass for EGP and SWP was 0.4 g and for BNP was 0.05 g. The values for initial concentration, pH, temperature and contact time were 100 mg/L, 5, 22oC and 2 hours, respectively. Ni(II) removal efficiencies using EGP, SWP and BNP were 66, 38 and 33%, respectively. Taking into account the result and optimum condition obtained on Ni(II) removal efficiency from aqueous solution using EGP, SWP and BNP, the Ni(II) removal efficiency using these biosorbents from landfill leachate was investigated. It was found to be significantly (P ≤ 0.05) lower than what was found from aqueous solution.
30

A model route to a brominated hydroxy[2,3-c]pyran- a potential precursor to extended quinones

Mei, Mawonga N. January 2008 (has links)
A thesis submitted in fulfilment of the requirements for the degree Magister Technologiae (Chemistry) in the Faculty of Applied Sciences, Department of Chemistry, Cape Peninsula University of Technology, 2008 / Green et al. attempted to synthesize linear naphthopyranquinones from a naphthyl dioxolane using a TiCl4 as a catalyst. They managed to synthesise an angular naphthopyran as well as a linear naphthopyran in low yield. They showed that reducing the steric strain at position 1 of the naphthyl dioxolane afforded a low percentage yield of the linear naphthopyran plus an angular one. This thesis describes the synthesis of linear naphthopyrans with an improved percentage yield using TiCl4 as a catalyst. This was achieved by placing a OMe group of less steric hinderance at position 1 and a Br atom at position 4 of a naphthyl dioxolane. The OMe group at position 1 was to allow isomerisation to occur at position 2, and the Br atom was to inhibit isomerisation at position 4, thereby inhibiting the formation of the angular naphthopyran.

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