Reliability assessment for medium voltage electrical network : a case study within Eskom distribution

Abstract: The main purpose of the Electrical Power System is to provide a safe and acceptable electricity supply to the customers, with a reasonable level of reliability. Within Eskom, the serious effect of the unreliable power supply is a perpetual concern. Distribution network system is still liable for more than 80% of the customer reliability issues with the majority of faults (70%) occurring on the Medium Voltage (MV) networks. This paper is aimed at identifying the issues that contribute to poor reliability within the MV network and mitigation factors. This is intended to assist electrical utilities effectively to investigate the affected network, and to be able to apply strategic reliability improvement plans to achieve optimal performance. A case study was used to conduct the research, and the study area focus was Taunus electrical supply area within Eskom’s Distribution

Statistical modelling of key body dimensions in developing a size chart for the full-figured, pear-shaped South African women

Anthropometric body measurement is a crucial process in the development of size charts for garment manufacturing. Body measurements differ between specific population groups, and garments catering for different populations must be manufactured based upon accurate size charts informed by accurate body measurements for that population. Amongst population groups, the full-figured, pear-shaped South African woman is a unique identifiable body type. This body type is not adequately catered for in garment manufacturing, as it requires a unique configuration of garments with different sizes for the upper and lower torso. The relative absence of well-fitting garments for this body type necessitates taking body measurements in order to develop a size chart to inform design and manufacturing of garments. The purpose of this paper is to develop a statistical model of key body dimensions (bust, waist and hip) to populate a size chart for the manufacturing of ready-to-wear garments for the full-figured, pear-shaped South African woman. A correlational research method using body measurements from purposively selected women of ages 25 to 55 years was carried out. After categorizing the height measurements into three groups, the means of body measurements for the medium height group were used to develop a size chart for sizes 16 to size 24, using principal component analysis (PCA) and least squares regression. Results showed that the bust, waist and hip values highly contribute towards body type sizing. The bust and hip were highly correlated at R2=0.996 (99.6%), and the model predicted the true value of the hip at R2=0.993 (99.3%). Bust measurement positively correlated to the waist at 93.8%, and the model predicted the true value of the waist at R2=0.880 (88%). Bust dimension was significant in predicting the hip and waist dimensions. Variances among hip dimensions in the current sizing were in 4 to 6 cm intervals. Full-figured, pear-shaped figures present 5.5 to 7.5 cm values across the hip measurements. In conclusion, findings of the simulated values for hip and waist at different sizes based on bust measurements suggest that the values obtained respectively were almost the same with measurements in the customised size chart developed in the study. This makes the model dependable, reliable and valid for the size chart determination targeting the full-figured, pear-shaped South African woman. It is recommended that the model be used for determining size charts for other body shapes

The impact of succession planning on the sustainability of cane production by small-scale cane growers in the north coast of Kwazulu-Natal, South Africa

This paper forms part of a research study for a PhD, which has been conducted in the North Coast of KwaZulu-Natal and focuses on the sustainability of emerging cane growers. The research problem of the study was that cane growers cannot be sustained beyond the current generation of existing farmers because young people are not interested. Agriculture takes place in rural areas which are characterised by high levels of poverty. Cane farming, like other agricultural production activities, is the major economic driver in these areas. However, the current cane growers are ageing and the economy will be negatively impacted unless the youth succeed their parents as farmers. Sustainability of cane production depends on the preparedness of the offspring of the cane growers to succeed them as farmers.The results of the study revealed two responses. The first response suggested that young people whose parents are cane growers are willing to succeed their parents and become cane growers. The second response suggested that where discussions on succession planning have taken place there was an increase in the number of young people indicating an interest in succeeding their parents. The paper concludes with a recommendation that there is a need for developing succession planning in the North Coast farming area.KEY WORDS: Cane grower, cane farmer, sustainability, succession planning, youth, extension implications

Genome-wide identification of breed-informative single-nucleotide polymorphisms in three South African indigenous cattle breeds

Access to genotyping assays enables the identification of informative markers that discriminate between cattle breeds. Identification of these markers can assist in breed assignment, improvement and conservation. The objective of this study was to identify breed informative markers to discriminate between three South African indigenous cattle breeds. Data from BovineSNP50 and GeneSeek Genomic Profiler (GGP-80K) assays were generated for Afrikaner, Drakensberger and Nguni, and were analysed for their genetic differentiation. Hereford and Angus were included as outgroups. Breeds were differentiated using principal component analysis (PCA). Single-nucleotide polymorphisms (SNPs) within the breeds were determined when minor allele frequency (MAF) was ≥ 0.05. Breed-specific SNPs were identified using Reynolds Fst and extended Lewontin and Krakauer's (FLK) statistics. These SNPs were validated using three African breeds, namely N’Dama, Kuri and Zebu from Madagascar. PCA discriminated among the breeds. A larger number of polymorphic SNPs was detected in Drakensberger (73%) than in Afrikaner (56%) and Nguni (65%). No substantial numbers of informative SNPs (Fst ≥ 0.6) were identified among indigenous breeds. Eleven SNPs were validated as discriminating the indigenous breeds from other African breeds. This is because the SNPs on BovineSNP50 and GGP-80K assays were ascertained as being common in European taurine breeds. Lower MAF and SNP informativeness observed in this study limits the application of these assays in breed assignment, and could have other implications for genome-wide studies in South African indigenous breeds. Sequencing should therefore be considered to discover new SNPs that are common among indigenous South African breeds and also SNPs that discriminate among these indigenous breeds

Epilepsy in rural South African children prevalence, associated disability and management

Objective. To determine the prevalence of epilepsy and its associated disabilities in rural South African children aged 2 - 9 years.Setting. Eight villages in the district of Bushbuckridge, Northern Province, South Africa_Design. A two-phase design was used_ The first phase involved screening children on a house-to-house baSis by interviewing mothers or caregivers using an internationally validated questionnaire for detecting childhood disability in developing countries. The second phase consisted of a paediatric/ neurodevelopmental assessment of the children who screened positive.Results. A total of 6692 children were screened; 722 (10.8%) had a paediatric evaluation and 49 (0.73%) had epilepsy. The· lifetime and active prevalences of epilepsy in these children were 7.3/1 000 and 6.7/1 000 respectively. Associated developmental disability was recorded in 35 affected children (71.4%), including 8 (16.3%) in whom this was moderate to severe. More than a half of the children with epilepsy (57.1%) did not receive anticonvulsant medication.Conclusion. The prevalence of epilepsy in the rural childhood population investigated is higher than that recorded in most similar studies from sub-Saharan Africa, and the poor utilisation of 'appropriate anticonvulsant treatment is cause for concern. This study highlights the paucity of relevant information on the epidemiology of epilepsy in South Africa and that the system available for its management, especially in rural areas, appears to have functional deficiencies. Appropriate research is needed to identify the problems in service delivery and to enable the planning and implementation of an appropriate primary health care-based system for the diagnosis and management of epilepsy in children

EFFECTS OF ORGANIC FERTILISERS ON GROWTH, YIELD AND NUTRITIONAL CONTENT OF SNOW PEAS (Pisum sativum var. saccharatum)

Snow peas (Pisum sativum var. saccharatum) are one of the widely used baby vegetable in Swaziland; however, there is a dearth of information pertaining to its organic production. A field study laid out in Factorial Randomised Complete Block Design was conducted at the Horticulture Farm, Luyengo Campus, of the University of Swaziland. Organic fertilisers used were kraal manure, broiler manure, and Igrow, applied at 20, 40, and 60 (t/ha). Inorganic fertilisers 2:3:2 (22) + 0.5% zinc and limestone ammonium nitrate (28%) were applied at 100 kg/ha and 80 kg/ha respectively. A trend of superiority of the different levels of organic manure application was observed as snow peas provided with 40 t/ha and 60 t/ha exhibited higher values in vegetative and reproductive growth, marketable yield and protein content especially on broiler and kraal manure application. The use of broiler manure at 40 t/ha and 60 t/ha in the production of vegetables like snow peas should be encouraged, because their application resulted in increased growth and yield compared to synthetic fertilisers

Can Reproductive Health Voucher Programs Improve Quality of Postnatal Care? A Quasi-Experimental Evaluation of Kenya’s Safe Motherhood Voucher Scheme

This study tests the group-level causal relationship between the expansion of Kenya’s Safe Motherhood voucher program and changes in quality of postnatal care (PNC) provided at voucher-contracted facilities. We compare facilities accredited since program inception in 2006 (phase I) and facilities accredited since 2010-2011 (phase II) relative to comparable non-voucher facilities. PNC quality is assessed using observed clinical content processes, as well as client-reported outcome measures. Two-tailed unpaired t-tests are used to identify differences in mean process quality scores and client-reported outcome measures, comparing changes between intervention and comparison groups at the 2010 and 2012 data collection periods. Difference-in-differences analysis is used to estimate the reproductive health (RH) voucher program’s causal effect on quality of care by exploiting group-level differences between voucher-accredited and non-accredited facilities in 2010 and 2012. Participation in the voucher scheme since 2006 significantly improves overall quality of postnatal care by 39% (p=0.02), where quality is defined as the observable processes or components of service provision that occur during a PNC consultation. Program participation since phase I is estimated to improve the quality of observed maternal postnatal care by 86% (p=0.02), with the largest quality improvements in counselling on family planning methods (IRR 5.0; p=0.01) and return to fertility (IRR 2.6; p=0.01). Despite improvements in maternal aspects of PNC, we find a high proportion of mothers who seek PNC are not being checked by any provider after delivery. Additional strategies will be necessary to standardize provision of packaged postnatal interventions to both mother and new-born. This study addresses an important gap in the existing RH literature by using a strong evaluation design to assess RH voucher program effectiveness on quality improvement

Being Surveyed Can Change Later Behavior and Related Parameter Estimates

Does completing a household survey change the later behavior of those surveyed? In three field studies of health and two of microlending, we randomly assigned subjects to be surveyed about health and/or household finances and then measured subsequent use of a related product with data that does not rely on subjects' self-reports. In the three health experiments, we find that being surveyed increases use of water treatment products and take-up of medical insurance. Frequent surveys on reported diarrhea also led to biased estimates of the impact of improved source water quality. In two microlending studies, we do not find an effect of being surveyed on borrowing behavior. The results suggest that limited attention could play an important but context-dependent role in consumer choice, with the implication that researchers should reconsider whether, how, and how much to survey their subjectsEconomic