The influence of rotational speed and pressure on the properties of rotary friction welded Titanium alloy (Ti‐6Al‐4V)

Abstract: This paper presents an investigation of rotary friction welding of 25.4 mm diameter Ti‐6Al‐4V rods. The weld process parameters used for this research were rotational speed, axial pressure and forging time. Only relative speed and axial pressure were the varied parameters while the forging time was kept constant. The mechanical properties of the weld joints were analysed and characterized. The results showed that the rotational speed and friction pressure have significant influence on the tensile strength, microstructure and weld integrity. As rotational speed increased heating time also increased in the weld, as a result, greater volume of material was affected by heat resulting in a wider width of the weld joint. Fine microstructure resulted due to an increased rotational speed and frictional pressure respectively. The oxidation and discolouration of welds were also discussed

Process optimization of rotary friction welding of Ti-6Al-4V alloy rods

Abstract: This paper presents an investigation on the performance of rotary friction welded 25.4 mm diameter Ti-6Al-4V alloy rods. The process parameters used are friction and forging pressure, rotational speed, forging time and upset distance. The heating time was determined by the amount of friction pressure and rotational speed utilised. The final weld joints were examined for mechanical properties. The results revealed that friction welding process parameters have significant influence on the weld joint properties and weld joint integrity. The hardness and ultimate tensile properties of the weld joints varied with the variation in rotational speed and axial pressure. The tensile properties of the weld joints were higher than the parent material at lower rotational speed or higher axial pressure. The weld width was proportional to relative motion and inversely proportional to axial pressure

Environmental and Economic Analysis of Selected Pavement Preservation Treatments

Pavements are one of the highest assets and represent massive investment. The need to design and provide a sustainable maintenance service is becoming a priority and this comes mutually with the intentions to reduce impacts caused by maintenance treatments to the environment. This paper through a case study presents a Life Cycle Cost and Assessment technique during a 30 year analysis period to measure the cost effectiveness, embodied energy and carbon emissions of selected preservation treatments. These treatments can either be applied separately or in combination during the preventive maintenance of road pavements. This study entails three life cycle phases of material extraction and production, transportation and construction of maintenance activities. Through a literature review, raw materials energy and emission inventory data was averaged followed by the analysis of the equipment involved by using the specific fuel consumption to calculate the energy and emissions spent by the machine and finally the selected treatment energy and emissions was computed. Results show that preservation treatments can have an LCC of 30-40 % and embodied energy and carbon emission of 3-6 times lower than the traditional approach. This study bridges gaps in literature on integrated evaluation of environmental and economic aspects of preservation treatments

Clinical and ultrasonographic features of abdominal tuberculosis in HIV positive adults in Zambia

Background: The diagnosis of abdominal tuberculosis (TB) is difficult, especially so in health care facilities in developing countries where laparoscopy and colonoscopy are rarely available. There is little information on abdominal TB in HIV infection. We estimated the prevalence and clinical features of abdominal (excluding genitourinary) TB in HIV infected adults attending the University Teaching Hospital, Zambia. Methods: We screened 5,609 medical inpatients, and those with fever, weight loss, and clinical features suggestive of abdominal pathology were evaluated further. A clinical algorithm was used to specify definitive investigations including laparoscopy or colonoscopy, with culture of biopsies and other samples. Results: Of 140 HIV seropositive patients with these features, 31 patients underwent full evaluation and 22 (71%) had definite or probable abdominal TB. The commonest presenting abdominal features were ascites and persistent tenderness. The commonest ultrasound findings were ascites, para-aortic lymphadenopathy (over 1 cm in size), and hepatomegaly. Abdominal TB was associated with CD4 cell counts over a wide range though 76% had CD4 counts <100 cells/μL. Conclusion: The clinical manifestations of abdominal TB in our HIV-infected patients resembled the well-established pattern in HIV-uninfected adults. Patients with fever, weight loss, abdominal tenderness, abdominal lymphadenopathy, ascites and/or hepatomegaly in Zambia have a high probability of abdominal TB, irrespective of CD4 cell count. © 2009 Sinkala et al; licensee BioMed Central Ltd

Outcomes of a remote, decentralized health center-based HIV/AIDS antiretroviral program in Zambia, 2003 to 2007

A cross-sectional study of patients living with HIV/ AIDS treated during 2003 to 2007 in decentralized, rural health centers in Zambia was performed to measure virological outcomes after 12 months of antiretroviral therapy and identify factors associated with virological failure. Data from 228 patients who started antiretroviral therapy >12 months prior were analyzed. In all, 93% received stavudine + lamivudine + nevirapine regimens, and median antiretroviral therapy duration was 23.5 months (interquartile range 20-28). Of the 205 patients tested for viral load, 177 (86%) had viral load <1000 copies/mL. Probability of developing virological failure (viral load >1000 copies/mL) was 8.9% at 24 months and 19.6% at 32 months. Predictors for virological failure were <100% adherence, body mass index <18.5 kg/m(2), and women <40 years old. Of those with virological failure who underwent 3 to 6 months of intensive adherence counseling, 45% obtained virological success. In a remote, resource-limited setting in decentralized health centers, virological and immunological assessments of patients on antiretroviral therapy >12 months showed that positive health outcomes are achievable

Occupational therapy students’ use of social media for professional practice

Background. The use of social media for professional practice is an emerging trend for healthcare professionals; however, limited literature exists on the phenomenon. Social media usage is prevalent among students, as it is incorporated into many health professions education curricula. This poses potential ethical dilemmas.Objective. To examine the nature of social media usage and knowledge of ethical considerations by occupational therapy (OT) students for professional purposes.Methods. A quantitative, cross-sectional survey was administered to the entire cohort of OT students (N=128) enrolled at the University of KwaZulu-Natal, Durban, South Africa in 2016. Data were analysed descriptively using Microsoft Excel 2013 (Microsoft, USA).Results. The most commonly used device to access social media was mobile phones, with WhatsApp and YouTube frequently used for both general and professional purposes. Uses included accessing social media for developing professional skills and knowledge, and in fulfilling academic requirements. Ethical dilemmas were evident among students, who indicated that social media ethical considerations should be incorporated into the curriculum.Conclusion. The study highlighted that most students use some form of social media as part of their professional practice, which has the potential to be used effectively to enhance learning opportunities. Future studies of a qualitative nature could shed light on students’ perceptions of social media and practical implications for practice

Investigating the role of the Public Private Partnership Act on private sector participation in PPP projects : A case of Zambia

In 2008, the Public Private Partnership (PPP) concept was identified by the Zambian Government as a vehicle for scaling up public infrastructure project delivery in the country. A platform for active private sector participation in the direct provision of public goods and services was created by enacting the PPP Act No. 14 of 2009. It was anticipated that this would encourage the local and international private sector to participate in delivering PPP projects. The aim of this research was therefore to investigate the role of this PPP Act on the private sector’s decision to participate in PPP projects in Zambia. A mixed method design was adopted for this research due to limited information and stakeholders on the ground. 43 industry practioners representing contractors, developers’ financiers and government were identified motivating a mixed method approach in order to obtain more data given a generally lower sample available. A total of 27 questionnaires were obtained. Findings revealed that the PPP Act had not played a significant role to influence private sector decision to participate in PPP projects. The findings from this research unlocks part of the reason why there is little participation by private sector in PPP projects. The research identifies presents areas of focus in amending the Act in order to attract and influence private investment in current critical areas such as energy, higher education and housing among others. The study recommends that the immediate revision of PPP Act to remove identified barriers which among others include inadequate and unclear governing PPP framework, obstruction by bureaucracy, inappropriate risk sharing mechanisms and absence of protection to the private sector stakeholders

Language identification for South African Bantu languages Using Rank Order Statistics

Language identification is an important pre-process in many data management and information retrieval and transformation systems. However, Bantu languages are known to be difficult to identify because of lack of data and language similarity. This paper investigates the performance of n-gram counting using rank orders in order to discriminate among the different Bantu languages spoken in South Africa, using varying test and training data sizes. The highest average accuracy obtained was 99.3% with a testing size of 495 characters and training size of 600000 characters. The lowest average accuracy obtained was 78.72% when the testing size was 15 characters and learning size was 200000 characters

Education and training experiences of early childhood care and education practitioners in rural and urban settings of Durban, South Africa

BACKGROUND : The education and training experiences of Early Childhood Care and Education (ECCE) practitioners reflect gaps and inequalities in South Africa's educational system. Most South African ECCE centre practitioners do not have the appropriate qualifications to provide quality education to young learners AIM : The study aimed to explore how the education and training experiences of ECCE practitioners impact their professional identity in urban and rural settings in KwaZulu-Natal province and to develop a model that would enhance the education and training of ECCE practitioners SETTING : Ten participants were selected for this study: one centre head and four practitioners from a rural setting, and one centre head and four practitioners from an urban area METHODS : Wenger's social theory of learning was used to obtain an in-depth understanding of ECCE practitioners' education and training experiences and how they function as professional workers. An interpretative, qualitative case study was adopted. Data was collected through focus group semi-structured interviews and non-participants' observation and then analysed thematically RESULTS : The findings revealed that practitioners in rural settings had to contend with unfair working conditions daily, working all day in challenging circumstances whilst earning low incomes. Urban practitioners worked reasonable hours and received living wages, although they also experienced challenges such as a lack of parental involvement, lack of transport for children and high rates of absenteeism CONCLUSION : Inequalities between rural and urban practitioners existed concerning resources, salaries, working conditions and further study and professional growth opportunities. Ensuring that practitioners attain proper Early Childhood Care (ECC) qualifications will raise the profession's esteem amongst wider communities.This article is based on the master’s thesis of Pam Zulu.http://www.sajce.co.zaam2023Early Childhood EducationEducation Management and Policy Studie