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Effect of LDHs and Other Clays on Polymer Composite in Adsorptive Removal of Contaminants: A Review
Get PDFArticleRecently, the development of a unique class of layered silicate nanomaterials has attracted
considerable interest for treatment of wastewater. Clean water is an essential commodity for healthier
life, agriculture and a safe environment at large. Layered double hydroxides (LDHs) and other clay
hybrids are emerging as potential nanostructured adsorbents for water purification. These LDH
hybrids are referred to as hydrotalcite-based materials or anionic clays and promising multifunctional
two-dimensional (2D) nanomaterials. They are used in many applications including photocatalysis,
energy storage, nanocomposites, adsorption, di usion and water purification. The adsorption and
di usion capacities of various toxic contaminants heavy metal ions and dyes on di erent unmodified
and modified LDH-samples are discussed comparatively with other types of nanoclays acting as
adsorbents. This review focuses on the preparation methods, comparison of adsorption and di usion
capacities of LDH-hybrids and other nanoclay materials for the treatment of various contaminants
such as heavy metal ions and dyes
A Distributed Stream Processing Middleware Framework for Real-Time Analysis of Heterogeneous Data on Big Data Platform: Case of Environmental Monitoring
Get PDFArticleIn recent years, the application and wide adoption of Internet of Things (IoT)-based
technologies have increased the proliferation of monitoring systems, which has consequently
exponentially increased the amounts of heterogeneous data generated. Processing and analysing
the massive amount of data produced is cumbersome and gradually moving from classical
‘batch’ processing—extract, transform, load (ETL) technique to real-time processing. For instance,
in environmental monitoring and management domain, time-series data and historical dataset are
crucial for prediction models. However, the environmental monitoring domain still utilises legacy
systems, which complicates the real-time analysis of the essential data, integration with big data
platforms and reliance on batch processing. Herein, as a solution, a distributed stream processing
middleware framework for real-time analysis of heterogeneous environmental monitoring and
management data is presented and tested on a cluster using open source technologies in a big data
environment. The system ingests datasets from legacy systems and sensor data from heterogeneous
automated weather systems irrespective of the data types to Apache Kafka topics using Kafka Connect
APIs for processing by the Kafka streaming processing engine. The stream processing engine executes
the predictive numerical models and algorithms represented in event processing (EP) languages
for real-time analysis of the data streams. To prove the feasibility of the proposed framework,
we implemented the system using a case study scenario of drought prediction and forecasting based
on the Effective Drought Index (EDI) model. Firstly, we transform the predictive model into a form
that could be executed by the streaming engine for real-time computing. Secondly, the model is
applied to the ingested data streams and datasets to predict drought through persistent querying of
the infinite streams to detect anomalies. As a conclusion of this study, a performance evaluation of
the distributed stream processing middleware infrastructure is calculated to determine the real-time
effectiveness of the framework
A Tale of Two Markets: Unequal Access to Private Property in a South African City
Get PDFArticleIn line with international trends, South Africa’s post-apartheid government has embarked on a
housing policy that emphasises asset building. Homeownership has become a dominant policy
for assisting the historically disadvantaged Black population. This paper looks at two property
markets in Mangaung, a metropolitan municipality that includes Bloemfontein. We analysed
property activity on 2,545 residential stands in former Black and former White areas in Mangaung
since 1990. Our findings show two distinct markets. The formal property market in former Black
areas shows a low number of transactions, low value and slow turnover. In the former White
areas, a housing investment made between 1990 and 2016 would have yielded an annual return of
14 per cent, but in the former Black areas only 7 per cent. This poor return makes it difficult for
homeowners in former Black areas to use housing for asset building
Bioactive Compounds and Functional Potential of Uapaca Kirkiana (Muell. arg.) Fruits
Get PDFArticleConsumption of Uapaca kirkiana indigenous fruit by the local populace is growing in
popularity because of the acclaimed health and functional benefits. The aim of the study
was to determine the bioactive compounds and functional properties of the U. kirkiana
fruit. Besides the fruit’s pulp yield, the bioactive phytochemical constituent,
physicochemical properties and functional characteristics of the pulp were analysed. The
sugar, starch, minerals, and ascorbic acid constituents of the fruit pulp were, respectively
determined using the following instruments: brix refractometer, megazyme kit, inductive
coupled plasma-optical emission spectrometer and 2,6-dichlorophenolindophenol
(DCPIP) titration test. The total phenolic content (TPC), tannin, and flavonoid contents
were evaluated using Folin Ciocalteau test, tannin binding test and vanillin test,
respectively. The average weight of the U. kirkiana fruits harvested from three regions
having different climatic conditions ranged from 23.56 to 34.20 g per fruit. The mean
pulp weight was from 12.15 g/100 g to 15.09 g/100 g per fruit. The biochemical and
functional parameters obtained include total titratable acid (0.3 - 0.48 g/kg), antioxidant
activity (34.96 - 36.68%), vitamin C (15.74 - 16.63 mg/100 g), dry matter content (28.81
- 29.38%), pH (4.3 - 4.6) and sugar content (20.29 - 21.87 g/100 g). Fructose was the
dominant sugar (10.12-11.0 g/100 g). Preliminary phytochemical screening of the pulp
indicated the presence of tannins, flavonoids, amino acids and carbohydrate content.
Total phenolic content ranged from 67.0 to 82.5 μg GAE/g. The essential elements
constituent evaluation of the pulp revealed that Fe content was 11.3 - 12.2 mg/100 g, K
(383.07 - 439.8 mg/100 g), Mg (28.7 - 35.1 mg/100 g), Ca (16.4 - 17.3 mg/100 g), P
(13.4 - 15.1 mg/100 g), Na (9.08 - 9.78 mg/100 g), Cu (0.8 - 0.94 mg/100 g) and Zn (0.87
- 0.94 mg/100 g). This study, besides establishing U. kirkiana fruit as a good source of
micronutrients (Fe, Cu, Zn), reveals that the fruit is also an excellent source of phenolic
compounds, vitamin C and sugars, hence use as a dietary supplement may combat some
nutritional deficiencies. We, therefore, recommend U. kirkiana fruits to be used to
produce nutritive functional foods with health benefits such as probiotic jams and as an
additive
Primary Mathematics Teachers’ Assessment Practices in the Context of the Integrated Primary Curriculum in Lesotho
Get PDFArticleThe purpose of this research was to investigate primary mathematics teachers’ assessment practices in the
context of the new integrated primary curriculum. This was a case study in which data were collected
through classroom observations and interviews. Findings from the study revealed that teachers were
able to use some of the assessment for learning strategies in their classrooms. These were
communicating learning intentions and success criteria at the beginning of the lessons, making use of
peer and self-assessment by learners. The study established that the use of success criteria can
promote learners’ self-reflective ability, regardless of their age. Findings also revealed that teachers were
not providing learners with descriptive feedback that showed their strengths and weaknesses.
Furthermore, the results of the study revealed that teachers encountered challenges in the
implementation of assessment for learning in their classrooms. Some of the challenges encountered
were a shortage of resources, high teacher–learner ratio, increased workload and reduced teaching time
Personal Factors, Forms of Capital And The Entrepreneurial Competence of Female Engineering And Construction SMME Owner/Managers In An Emerging Economy Context
Get PDFArticleThe role of entrepreneurship in tourism destination growth is critical as small businesses provide
services and fulfil the socio-economic opportunities of domestic and foreign tourists. Although personal
traits (e.g. age and gender) and the different capital forms possessed by entrepreneurs are often touted
in explaining entrepreneurial competence, it remains unclear what explains the entrepreneurial
competence of female entrepreneurs especially those operating in predominantly male-oriented
industries. To address this research gap, the study examined the effects of personal demographic
variables (i.e. race, age, and education) and different capital forms (i.e. social capital, cultural capital
and emotional capital) on the entrepreneurial competence of female owned/managed SMMEs operating
in engineering and construction industry in a South African province. A descriptive, cross-sectional
survey was conducted on 336 female owners/managers of SMMEs operating engineering and
construction businesses in the Free Province. A set of statistical techniques (namely T tests, ANOVA,
correlation analysis and regression analysis) were conducted to test the proposed relationships
between these foresaid constructs. The results revealed a strong, positive and statistically significant
relationship between different demographic characteristics and entrepreneurial competence.
Surprisingly, only emotional capital was significantly and positively correlated with entrepreneurial
competence. Lastly, while all three capital forms significantly predicted entrepreneurial competence,
emotional capital had the strongest effect. The study provides some valuable insights into the
determinants of entrepreneurial competence which could be instrumental to the success and survival
of emerging female owned/managed SMMEs in engineering and construction industry, an industrial
domain where female entrepreneurs are yet to be seriously considered
Determining African Students’ E-Learning Readiness To Improve Their E-Learning Experience
Get PDFArticleE-learning connects two elements of education - learning and technology. Technology can become an enabler for learning when correctly applied. However, its success, to a degree, is dependent on the self-motivation of individuals to implement self-directed learning. One way to apply technology in higher education, and to determine if students are engaging in self-directed learning, is by implementing on-line assessments. However, the readiness of students may sometimes be ignored when planning and designing an e-learning assessment. The purpose of this article is to assess the e-learning readiness of engineering and information technology students in order to better support and improve their e-learning experience. The research followed a quantitative approach where about 50% of the students who participated agreed that they are comfortable with performing searches, downloading files and setting bookmarks (this relates to self-efficacy). For self-direction, the majority of the students were neutral when asked if they could set goals and deadlines for themselves. A recommendation is that developers could improve the required programming software platforms to suit all devices by using usability models that include ease of use and perceived usefulness. Additionally, these students need more academic support, especially with regard to developing time management and problem-solving skills
The Development Of A Framework For The Management Of Suppliers As Part Of Public Procurement Management And Supply Chaim Management Practices In District Municipalities Of The Free State Province
Get PDFPublic-sector procurement practices are the biggest single consumer of allocation in most countries. Procurement of the organs of state varies between 5% and 8% of the gross domestic product (GDP) in most industrialised countries (Ambe and Badenhorst-Weiss, 2012:244). During 2013/2014 the South African public sector spent R500 billion on goods, services and on construction work (National Treasury, RSA, 2015b:3). This indicates that public procurement fulfil a vital role in any country in that it has important economic and political implications. Therefore, the South African government has to ensure that public procurement processes are economical and efficient. Government procurement spending has created opportunities for Small, Medium and Micro-Enterprises (SMMEs) to grow the economy and create jobs.
In South Africa, the government uses a large share of its fiscus to procure goods, services and infrastructural needs from SMMEs suppliers for communities due to the developmental needs of the historical past. It is therefore an imperative to enhance the efficiency of supplier management as part of the procurement management and SCM (SCM) practices in all municipalities and for the purpose of this study in district municipalities of the Free State Province.
Since 1995, the South Africa government embarked upon financial management reforms, including reforms of procurement management systems to, amongst others, address the inefficiencies in government procurement practices, contract management and asset control, particularly in municipalities. Since the inception of these reforms all municipalities have been responsible for implementing the principles of the system of Supply Chain Management (SCM) to manage infrastructure, goods and services, including contracts awarded to SMMEs suppliers, in an effective manner.
This study shows that municipalities in the Free State Province have defaulted on timeous payment to their suppliers and other creditors when compared to other municipalities in other provinces. The challenge of late and non-payment of suppliers has had an adverse financial effect on municipalities, townships and rural businesses, as well as on youth and women-owned SMMEs. However, it was noted that the challenge of late and non-payment of the Free State SMME suppliers still persists, which has a ripple effect on the township and rural business, as well as on youth and woman-owned SMMEs. It is now spreading to the communities. In this regard most of the municipalities in the Free State Province fell behind with their payments for bulk purchases of electricity and water to Eskom by R2,5 billion and water boards by R2,5 billion outstanding on 30 June 2017. In addition, the Auditor-General (AGSA) cautioned that the continued disregard for procurement processes in municipalities of the Free State resulted in irregular expenditure that created an environment open to misappropriation, wastage and the abuse of public funds. The appointment of contractors and suppliers without following the competitive bidding process resulted in irregular expenditure in most of the municipalities in the Free State Province (AGSA, RSA, 2017:55-56). Thus, one could argue that most municipalities of the Free State disregard SCM policies and procedures that resulted in non-payment or late payment to suppliers and irregular expenditure.
The aim of this study was to promote effective procurement and SCM practices positively by developing a framework for the management of suppliers as part of public procurement and SCM practices in district municipalities of the Free State Province. The proposed framework, provides a coherent and holistic step by step approach by identifying key components and criteria required to promote and improve the management of suppliers as part of public procurement management and SCM practices in district municipalities and affiliated local municipalities of the Free State Province in an effective manner. The following elements are emphasised in the proposed framework for the management of suppliers as part of public procurement management and SCM practices in district municipalities of the Free State Province, namely supplier selection, supplier relationship management, supplier performance evaluation and certification and supplier development. Each of these elements are influenced by particular factors.
In addition to the proposed framework for the management of suppliers as part of public procurement management and SCM practices in district municipalities of the Free State Province, the following was recommended to improve the management of suppliers as part of public procurement management and SCM practices. The accounting officer of all district municipalities of the Free State Province and affiliated local municipalities must ensure that all money owed by the municipality must be paid within 30 days of receiving the relevant invoice or statement, unless prescribed otherwise for certain categories of expenditure. All district municipalities of the Free State Province and affiliated local municipalities must give effect to the requirements of the Municipal Financial Management Act (MFMA) (RSA, 2003), the Preferential Procurement Policy Framework Act (PPPFA) (RSA, 2000), and the amended Preferential Procurement Regulations (PPR) (RSA, 2017a) to promote the effective management of procurement and SCM systems. All district municipalities of the Free State Province and affiliated local municipalities must plan for all their procurement and SCM needs during the strategic planning process (National Treasury, RSA, 2017a). The selection of suppliers should be managed in terms of the requirements of the Municipal SCM Regulation of the MFMA (RSA, 2005b) and National Treasury SCM Instruction Note 4A (RSA, 2016f), which require that price quotations be invited and accepted from prospective suppliers listed on the CSD (National Treasury, RSA, 2005b; National Treasury, RSA, 2016f). Provision should be made to select more previously disadvantaged female and disabled suppliers. The Municipal Public Accounts Committees (MPAC) must investigate tenders awarded to people working in the municipality.
Except for the above recommendations the following were also recommended; The skills levels of procurement officials need to be upgraded to enable them to implement procurement management practices effectively. Each municipality and municipal entity should have standard training programmes designed to empower SMMEs on procurement practices. Adequate monitoring and evaluation on municipal procurement management practices is critical to ensure appliance of MFMA, (RSA, 2003), National Treasury (RSA, 2005b) and other applicable Acts and regulations. Practitioners who are hired in the municipal procurement sections or SCM units should have proper procurement and SCM qualifications and experience. Procurement and SCM regulations, policies, delegations, and Codes of Conduct should be discussed quarterly amongst procurement management and practitioners. The skills levels of procurement officials need to be upgraded to enable them to deal with new SCM challenges
Investigation Of The Influence Of Information And Communication Technologies On Sustainable Road Transportation In Bloemfontein City, South Africa
Get PDFDissertationThe concept of sustainable road transportation as an important measure of sustainable development has been adopted globally, by different countries and cities after the Brundtland report, along with other environmental initiatives that have aimed to sustain and make the planet liveable for future generation. African cities have also taken the initiative to move towards sustainability of transportation in their cities. Different scholars have identified various sustainable road transportation indicators as a guide to what governments and policy makers need to focus on to solve different challenges the cities are facing. Although different policies have been effective in some cities, there are other challenges that have not been alleviated, such as congestion, traffic delays, carbon emissions, and the dominant use of private vehicles. The incorporation of Information and Communication Technology (ICT) in sustainable road transportation is argued to be one of the ways to make road transportation efficient and effective. This could alleviate challenges such as congestion, carbon emissions, and the use of public transportation, and help make road transportation and cities sustainable. However, literature is scarce on how integration of ICT will influence sustainability of road transportation, in particular in cities of South Africa. Therefore, using the study context of Bloemfontein city of South Africa, this study examined the current scenario of the road transportation system in city and explored how sustainable road transportation in the city can be achieved by use of relevant innovative systems like Information and Communication Technologies (ICT) in the daily personal and professional activities of people and their travel needs in and around the city.
The study followed a quantitative research method. Data was collected by the use of survey method and was followed by statistical analyses and empirical modelling. The findings indicate that the integration of ICT into road transportation reduces the need for travel and consequently reduces the levels of congestion on the road, which will lead to reduced CO₂ emissions. Through the results, it can be recommended that for Bloemfontein to be a sustainable city, the integration of ICT into road transportation should be a priority, which can assist to alleviate the existing transportation challenges and provide transportation that is sustainable, reliable, safe, efficient and cost effective
Impact Of Laser Powder Bed Fusion Process Defects On Mechanical Properties Of Ti6Al4V Mandible Implants
Get PDFDissertationEach year millions of patients’ quality of life is improved through surgical procedures
involving medical implanted devices. The need for new implants, treatments and prostheses,
as well as prolonging the life span of current implants has increased; the global prosthetics and
orthotics market size is expected to reach $11.7 billion by 2025, as indicated in Healthcare
Market Report (2020). Additive manufacturing (AM) was implemented in the medical field
fairly recently. Despite the enormous contribution medical devices have made to the public
health, there is a fear of possible liability exposure in the event of device malfunction or failure.
Efficient quality control of implants produced by new AM technologies is an important task
for suppliers in order to be in full compliance with existing regulations and certification of such
implants. If any defects occur, implant strength will directly influence the part’s mechanical
properties and performance, leading to the redistribution of stress and change in displacements
affecting attached bone tissue and mineral matrix of the bone, resulting in implant failure. For
wide applications in the medical industry, it is crucial that AM implants comply with
international standards with regard to their mechanical properties. Three point bending tests
(TPB) were carried out in this work on AM Ti6Al4V ELI specimens. TPB is a common tool
used to characterize bone material properties and mechanical performance of biomaterials.
Powder bed fusion is the unique AM method to produce metal objects with complex geometries
and internal structures; it permits the manufacture of complex-shaped functional 3D objects
such as customized implants. The benefits of AM in bone reconstruction using metal alloys are
unquestionable in terms of customization of implants and production time. Comprehensive
analysis of the laser powder bed fusion (LPBF) process together with functional anatomy
biomechanics of the human mandible was done in this work. Some case studies on defects
found in LPBF implants were evaluated. Based on biomechanics of the human mandible, LPBF
Ti6Al4V ELI samples were designed. Experiments and numerical simulations of samples with
sizes and placements of artificial pores were done. All samples were tested perpendicular to
the vertical building direction and showed no signs of failure at a single loading pattern. Defects
were designed and induced in the additive manufacturing of test samples of titanium, with
different size and placement. Results indicate that defects of 1000 μm×300 μm×210 μm and
1000 μm×500 μm×420 μm at various depth to the neutral axis had no significant outcome on
the mechanical performance of the samples with size of 100 mm 15 mm 2.5 mm when it
was tested statically at loading of 800, 900 and 1500 N, representing a maximum biting force.
This approach is a promising method of setting up a critical pore size to failure tolerance for
AM implants with some defects