Manufacturing of continuous flow equipment
- Authors: Strydom, Martin
- Date: 2018
- Subjects: Microfluidics , Nanofluids Micro-reactor
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35818 , vital:33850
- Description: For the work of this thesis a proof of concept microreactor and pump have been designed. Open source technology was used where possible to reduce the manufacturing cost. The pump is a pseudo HPLC/Syringe pump hybrid which adopts designs from both pumping systems. It works by charging two volumes of liquid into the primary chamber while the secondary chamber discharges. When the charge of the primary chamber is complete half of the liquid is pumped into the secondary chamber and the other half gets discharged. This has the benefit of sharing a common drive to reduce cost. The pump did function; however, the 3D printed parts did not have sufficient rigidity to offset mechanical stress, thus flexing occurred. The micro-reactor that was developed, was unique to commercial units. It was not chemically or thermally bonded but clamped with a gasket sealing the channels. This provides the advantage of unblocking inert material in the reactor. The reactor disk that was clamped was a super alloy, namely, Hastelloy C276. The reactor was tested against two commonly used reactors, namely, Chemtrix3227 and Little Things Factory (MS+VS). A simple synthesis of ethyl acetate has been used as a model reaction for comparing. The test reactor did not perform as well as the commercial counterparts, however probable causes have been identified for potential future work. Both the pump and the reactor worked as a proof of concept system, however further development is required for commercialisation.
- Full Text:
- Date Issued: 2018
- Authors: Strydom, Martin
- Date: 2018
- Subjects: Microfluidics , Nanofluids Micro-reactor
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35818 , vital:33850
- Description: For the work of this thesis a proof of concept microreactor and pump have been designed. Open source technology was used where possible to reduce the manufacturing cost. The pump is a pseudo HPLC/Syringe pump hybrid which adopts designs from both pumping systems. It works by charging two volumes of liquid into the primary chamber while the secondary chamber discharges. When the charge of the primary chamber is complete half of the liquid is pumped into the secondary chamber and the other half gets discharged. This has the benefit of sharing a common drive to reduce cost. The pump did function; however, the 3D printed parts did not have sufficient rigidity to offset mechanical stress, thus flexing occurred. The micro-reactor that was developed, was unique to commercial units. It was not chemically or thermally bonded but clamped with a gasket sealing the channels. This provides the advantage of unblocking inert material in the reactor. The reactor disk that was clamped was a super alloy, namely, Hastelloy C276. The reactor was tested against two commonly used reactors, namely, Chemtrix3227 and Little Things Factory (MS+VS). A simple synthesis of ethyl acetate has been used as a model reaction for comparing. The test reactor did not perform as well as the commercial counterparts, however probable causes have been identified for potential future work. Both the pump and the reactor worked as a proof of concept system, however further development is required for commercialisation.
- Full Text:
- Date Issued: 2018
Teachers' support of learners with attention deficit hyperactivity disorder (ADHD) in mainstream grade 10 classes: a case study
- Authors: Hendriks, Ivy Johleen
- Date: 2018
- Subjects: Attention-deficit-disordered children -- Education (Higher) , Hyperactive children -- Education (Higher)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/9033 , vital:34184
- Description: Attention Deficit Hyperactivity Disorder (ADHD) affects between 5 – 7 percent of children in the United States and Europe, making it one of the most common child psychiatric diagnoses. ADHD currently affects approximately 3 – 5 percent of school-going children and adolescents in South Africa. Schools create multiple challenges for learners with ADHD who show classic symptoms of inattention, hyperactivity and impulsivity. These symptoms produce impairment across cognitive, behavioural and interpersonal domains of function. Symptoms frequently manifest in a school setting, thus teachers play a central role in reporting symptoms, advising parents to seek professional assessment and assisting children with ADHD to achieve academically and socially. In line with the Education White Paper 6 of 2001, teachers should not only support learners with ADHD, but need to help these learners to understand and accept themselves as learners. The Literature focus on teachers’ knowledge of the characteristic symptoms displayed by learners with ADHD; teachers’ role in identifying and referring learners with ADHD; challenges faced by teachers when teaching learners with ADHD as well as teaching strategies and classroom accommodations teachers employ to effectively support learners with ADHD. The research was undertaken as a qualitative case study with an interpretivist underpinning. Data was collected making use of open-ended questionnaires, semi structured interviews and an informal observation. Purposive sampling was used to identify 6 teachers from previously disadvantaged high schools, teaching either Mathematics or a Language. The findings of the study indicated that teachers in mainstream high schools do not possess adequate knowledge to identify and refer learners with ADHD. As assumed by the researcher, the teachers’ lack of knowledge leads to unsuitable teaching strategies and classroom accommodations. Their biggest challenge to effectively support learners with ADHD was a lack of support and knowledge.
- Full Text:
- Date Issued: 2018
- Authors: Hendriks, Ivy Johleen
- Date: 2018
- Subjects: Attention-deficit-disordered children -- Education (Higher) , Hyperactive children -- Education (Higher)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/9033 , vital:34184
- Description: Attention Deficit Hyperactivity Disorder (ADHD) affects between 5 – 7 percent of children in the United States and Europe, making it one of the most common child psychiatric diagnoses. ADHD currently affects approximately 3 – 5 percent of school-going children and adolescents in South Africa. Schools create multiple challenges for learners with ADHD who show classic symptoms of inattention, hyperactivity and impulsivity. These symptoms produce impairment across cognitive, behavioural and interpersonal domains of function. Symptoms frequently manifest in a school setting, thus teachers play a central role in reporting symptoms, advising parents to seek professional assessment and assisting children with ADHD to achieve academically and socially. In line with the Education White Paper 6 of 2001, teachers should not only support learners with ADHD, but need to help these learners to understand and accept themselves as learners. The Literature focus on teachers’ knowledge of the characteristic symptoms displayed by learners with ADHD; teachers’ role in identifying and referring learners with ADHD; challenges faced by teachers when teaching learners with ADHD as well as teaching strategies and classroom accommodations teachers employ to effectively support learners with ADHD. The research was undertaken as a qualitative case study with an interpretivist underpinning. Data was collected making use of open-ended questionnaires, semi structured interviews and an informal observation. Purposive sampling was used to identify 6 teachers from previously disadvantaged high schools, teaching either Mathematics or a Language. The findings of the study indicated that teachers in mainstream high schools do not possess adequate knowledge to identify and refer learners with ADHD. As assumed by the researcher, the teachers’ lack of knowledge leads to unsuitable teaching strategies and classroom accommodations. Their biggest challenge to effectively support learners with ADHD was a lack of support and knowledge.
- Full Text:
- Date Issued: 2018
The mangroves of Mozambique: pathways to conservation through integrated management
- Macamo, Célia, Bandeira, Salomão
- Authors: Macamo, Célia , Bandeira, Salomão
- Date: 2018
- Subjects: Mangrove ecology -- Mozambique , Mangrove conservation -- Mozambique
- Language: English
- Type: Thesis , Doctorate , Dphil
- Identifier: http://hdl.handle.net/10948/30843 , vital:31182
- Description: This study analyses the status and management of mangroves in Mozambique and how the management system addresses the threats to mangrove conservation. A comprehensive analysis of the country forest condition and management status was conducted based on a literature review and informal interviews with key informants. GIS and remote sensing techniques combined with groundtruthing were used to assess the impact of natural and human threats on mangroves based on changes in NDVI (Normalised Difference Vegetation Index) and cover area. These studies were conducted at the Save River and Cabo Delgado province, respectively. Structural data of the mangrove forest were collected during field visits to assess changes in structural parameters and compare impacts in different forests or locations within the same forest. Finally a community-based management system in Nhangau (Sofala province) was analysed in order to assess the efficacy as a management tool to meet mangrove conservation objectives. Mozambique has an estimated mangrove cover area of 3 054 km2. In general there is a trend of decrease in cover around major human settlements, while remote areas show an increase in cover as documented in Maputo Bay (175.96 km2, decreasing within Maputo town) and Zambezi Delta (370.34 km2, increasing), respectively. Mangroves are mostly used for wood resources, salt production and fishing grounds. However, urban development, saltpans, logging and natural phenomena such as floods and cyclones are a threat to these systems. Mozambique has 27% of its mangroves protected in conservation areas. At places like the Quirimbas National Park, this protection is not effective due to illegal cutting and poor enforcement. The Mozambican institutional and legal frameworks provide protection to mangroves at all levels and prohibit all forms of degradation and unsustainable use. However law enforcement and institutional functioning is weak. There is also a need to update the legislation by adding specific aspects related to mangroves, such as regulating invertebrate collection and defining customary use. At the Save River changes in NDVI indicated that 63.42 km2 of mangrove (47.8%) were affected by cyclone Eline. Field investigations 11 years after the cyclone showed that there was substantial recovery in the protected creek forest but changes in sedimentation prevented recovery in the seaward sites that are exposed to storm surges and wind. This study highlighted the necessity for field based investigations in addition to remote sensing as results showed site specific differences. The percentage of living trees at the creek forest ranged from 71 to 97% from the outer to inner forest. Also species density was higher at the creek sites from the outer (101 ± 63 tree/ha) to inner forest (488 ± 111 trees/ha) as was the complexity index (0.09 to 0.25 respectively). At the seaward forest the percentage of living trees increased from 0 to 79% from the outer to inner forest. Seedlings (up to 40 cm height) dominated the understory throughout the forest however the outer edge of the seaward forest had no regeneration at all. This forest recovered naturally from the cyclone, however it is important to maintain low exploitation levels to ensure forest resilience in case of similar future impacts. The frequency and intensity of cyclones is expected to increase with climate change and thus the results can contribute to management strategies and climate change adaptation plans. 3 Human impacts were investigated at a peri-urban, rural and island setting in Cabo Delgado province. It was hypothesized that peri-urban forests would be more impacted. However an analysis of LandSat images showed that mangrove cover at the peri-urban site actually increased by 22.7% between 1991 and 2013; while rural forests lost 23.2% of its area during the same period. Field studies showed that there was no significant difference between average tree density for the different sites (p= 0.16) and the low complexity indices indicated young disturbed forests. At the peri-urban and rural sites, the tree diameter class 5.1-8 cm was targeted for extraction, while at the rural island all size classes were targeted. The proportion of stump:living trees was 1:11 at the peri-urban site; 1:9 at the rural site and 1:4 at the rural island. Most of the standing trees were crooked and not suitable for building purposes. The small extractive use of mangroves at the peri-urban site could be related to the fact that the dominant ethnic group has kept its essentially agricultural habits while at the rural site the people are typically fishermen and marine invertebrate collectors that rely on mangroves and marine resources for their livelihoods. Proposed management measures for these sites include raising awareness at all sites and conducting mangrove restoration at the peri-urban (abandoned saltpans and aquaculture farm) and rural sites. A community-based management system at Nhangau (Sofala province) was analysed in order to assess how this has achieved management conservation objectives. After facing several impacts due to mangrove degradation, the community of Nhangau engaged in mangrove replanting and management. The main management actions were (1) reduction of extractive uses, (2) continuous awareness and mangrove planting and (3) law enforcement. The restoration interventions started in the late 1990s by the local government in partnership with the local community and NGOs. Currently (2018), most of the activities are led by the local Natural Resources Management Committee (NRMC). Ten hectares of mangrove were planted between 1996 and 2017, and according to the local community the restored areas are already providing important ecological services such as temperature regulation. There are several challenges such as, limited functionality of the NRMC and its interaction with other stakeholders, Government representatives and local NGOs. There is also a lack of alternative livelihoods for mangrove cutters and the wider Nhangau community. Improvements to the system include better integration of local government representative structures with the civil society organizations (NGO and NRMC), law enforcement, financing of the appropriate sustainable use practices, environmental awareness and education and the promotion of appropriate NRMC functionality and representation. With these improvements this community-based management system can be effective as a management tool to meet mangrove conservation objectives and serve as a replicable model for other parts of the country. In conclusion, this research has documented both anthropogenic and climate-related impacts on mangroves in Mozambique and highlighted options for mangrove management focusing at strengthening the community –based management of mangroves in rural sites. Mangrove management would improve significantly by strengthening the legislation on specific mangrove issues combined with law enforcement and better community organization and their training and sensitization to manage mangrove resources at the local level. Such actions will increase the resilience of forests, allowing sustainable use and faster recovery in case of impacts by either anthropogenic or natural factors such as cyclones.
- Full Text:
- Date Issued: 2018
- Authors: Macamo, Célia , Bandeira, Salomão
- Date: 2018
- Subjects: Mangrove ecology -- Mozambique , Mangrove conservation -- Mozambique
- Language: English
- Type: Thesis , Doctorate , Dphil
- Identifier: http://hdl.handle.net/10948/30843 , vital:31182
- Description: This study analyses the status and management of mangroves in Mozambique and how the management system addresses the threats to mangrove conservation. A comprehensive analysis of the country forest condition and management status was conducted based on a literature review and informal interviews with key informants. GIS and remote sensing techniques combined with groundtruthing were used to assess the impact of natural and human threats on mangroves based on changes in NDVI (Normalised Difference Vegetation Index) and cover area. These studies were conducted at the Save River and Cabo Delgado province, respectively. Structural data of the mangrove forest were collected during field visits to assess changes in structural parameters and compare impacts in different forests or locations within the same forest. Finally a community-based management system in Nhangau (Sofala province) was analysed in order to assess the efficacy as a management tool to meet mangrove conservation objectives. Mozambique has an estimated mangrove cover area of 3 054 km2. In general there is a trend of decrease in cover around major human settlements, while remote areas show an increase in cover as documented in Maputo Bay (175.96 km2, decreasing within Maputo town) and Zambezi Delta (370.34 km2, increasing), respectively. Mangroves are mostly used for wood resources, salt production and fishing grounds. However, urban development, saltpans, logging and natural phenomena such as floods and cyclones are a threat to these systems. Mozambique has 27% of its mangroves protected in conservation areas. At places like the Quirimbas National Park, this protection is not effective due to illegal cutting and poor enforcement. The Mozambican institutional and legal frameworks provide protection to mangroves at all levels and prohibit all forms of degradation and unsustainable use. However law enforcement and institutional functioning is weak. There is also a need to update the legislation by adding specific aspects related to mangroves, such as regulating invertebrate collection and defining customary use. At the Save River changes in NDVI indicated that 63.42 km2 of mangrove (47.8%) were affected by cyclone Eline. Field investigations 11 years after the cyclone showed that there was substantial recovery in the protected creek forest but changes in sedimentation prevented recovery in the seaward sites that are exposed to storm surges and wind. This study highlighted the necessity for field based investigations in addition to remote sensing as results showed site specific differences. The percentage of living trees at the creek forest ranged from 71 to 97% from the outer to inner forest. Also species density was higher at the creek sites from the outer (101 ± 63 tree/ha) to inner forest (488 ± 111 trees/ha) as was the complexity index (0.09 to 0.25 respectively). At the seaward forest the percentage of living trees increased from 0 to 79% from the outer to inner forest. Seedlings (up to 40 cm height) dominated the understory throughout the forest however the outer edge of the seaward forest had no regeneration at all. This forest recovered naturally from the cyclone, however it is important to maintain low exploitation levels to ensure forest resilience in case of similar future impacts. The frequency and intensity of cyclones is expected to increase with climate change and thus the results can contribute to management strategies and climate change adaptation plans. 3 Human impacts were investigated at a peri-urban, rural and island setting in Cabo Delgado province. It was hypothesized that peri-urban forests would be more impacted. However an analysis of LandSat images showed that mangrove cover at the peri-urban site actually increased by 22.7% between 1991 and 2013; while rural forests lost 23.2% of its area during the same period. Field studies showed that there was no significant difference between average tree density for the different sites (p= 0.16) and the low complexity indices indicated young disturbed forests. At the peri-urban and rural sites, the tree diameter class 5.1-8 cm was targeted for extraction, while at the rural island all size classes were targeted. The proportion of stump:living trees was 1:11 at the peri-urban site; 1:9 at the rural site and 1:4 at the rural island. Most of the standing trees were crooked and not suitable for building purposes. The small extractive use of mangroves at the peri-urban site could be related to the fact that the dominant ethnic group has kept its essentially agricultural habits while at the rural site the people are typically fishermen and marine invertebrate collectors that rely on mangroves and marine resources for their livelihoods. Proposed management measures for these sites include raising awareness at all sites and conducting mangrove restoration at the peri-urban (abandoned saltpans and aquaculture farm) and rural sites. A community-based management system at Nhangau (Sofala province) was analysed in order to assess how this has achieved management conservation objectives. After facing several impacts due to mangrove degradation, the community of Nhangau engaged in mangrove replanting and management. The main management actions were (1) reduction of extractive uses, (2) continuous awareness and mangrove planting and (3) law enforcement. The restoration interventions started in the late 1990s by the local government in partnership with the local community and NGOs. Currently (2018), most of the activities are led by the local Natural Resources Management Committee (NRMC). Ten hectares of mangrove were planted between 1996 and 2017, and according to the local community the restored areas are already providing important ecological services such as temperature regulation. There are several challenges such as, limited functionality of the NRMC and its interaction with other stakeholders, Government representatives and local NGOs. There is also a lack of alternative livelihoods for mangrove cutters and the wider Nhangau community. Improvements to the system include better integration of local government representative structures with the civil society organizations (NGO and NRMC), law enforcement, financing of the appropriate sustainable use practices, environmental awareness and education and the promotion of appropriate NRMC functionality and representation. With these improvements this community-based management system can be effective as a management tool to meet mangrove conservation objectives and serve as a replicable model for other parts of the country. In conclusion, this research has documented both anthropogenic and climate-related impacts on mangroves in Mozambique and highlighted options for mangrove management focusing at strengthening the community –based management of mangroves in rural sites. Mangrove management would improve significantly by strengthening the legislation on specific mangrove issues combined with law enforcement and better community organization and their training and sensitization to manage mangrove resources at the local level. Such actions will increase the resilience of forests, allowing sustainable use and faster recovery in case of impacts by either anthropogenic or natural factors such as cyclones.
- Full Text:
- Date Issued: 2018
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