Inefficient compressed air systems in deep-level mines deteriorate energy performance and increase operational costs. Leaks, wastages, and misuse are common inefficiencies that necessitate an oversupply of compressed air. It is therefore important to identify where the opportunities for improvement are located. Underground mining equipment can be used to develop a zero-waste compressed air demand profile. This profile can then be simulated for the entire operation to determine a theoretical baseline. Noticeable inefficiencies are then identified by comparing the actual data with the zero-waste baselines. The results of this study showed that the surface operations oversupply compressed air by 15% (10 kg/s of air) per day. This requires an additional 80 MWh of electricity (14.5% of the total) and costs approximately R91 000 per day. The comparison with the zero-waste baselines showed that 7.9 kg/s of air is wasted at the underground levels during drilling periods, highlighting the areas that require mitigation projects to improve the performance while decreasing costs and wastages.

Ondoeltreffende saamgeperste lugstelsels in diepvlakmyne verswak energieprestasie en verhoog bedryfskoste. Lekkasies, vermorsing en misbruik is algemene ondoeltreffendhede wat 'n ooraanbod van saamgeperste lug noodsaak. Dit is dus belangrik om te identifiseer waar daar geleenthede vir verbetering is. Ondergrondse mynboutoerusting kan gebruik word om 'n geen-afval-aanvraagprofiel vir saamgeperste lug te ontwikkel. Hierdie profiel kan dan vir die hele operasie gesimuleer word om 'n teoretiese basislyn te bepaal. Opmerklike ondoeltreffendheid word dan geidentifiseer deur die werklike data te vergelyk met die nul-afval basislyne. Die resultate van hierdie studie het getoon dat die oppervlakbewerkings saamgeperste lug met 15% (10 kg/s lug) per dag oorvoorsien. Dit benodig 'n bykomende 80 MWh elektrisiteit (14,5% van die totaal) en kos ongeveer R91 000 per dag. Die vergelyking met die nul-afval basislyne het getoon dat 7,9 kg/s lug tydens boorperiodes op die ondergrondse vlakke vermors word, wat die gebiede beklemtoon wat versagtingsprojekte vereis om die werkverrigting te verbeter terwyl koste en vermorsing verminder word.

BACKGROUND. Careful consideration of an increasingly underprepared tertiary student population, the limited use of simulation in South African (SA) healthcare education and a changing healthcare education milieu is required from SA educators when implementing, evaluating and revising simulation integration. OBJECTIVES. To develop a conceptual framework for the integration of simulation in the SA undergraduate physiotherapy programme. METHODS. A non-experimental descriptive research design was used. A purposive sample of 15 healthcare educationalists from SA and abroad were approached to participate in a modified Delphi survey, informed by the results obtained from a systematic review identifying simulation integration framework elements. Data were analysed as percentages, with feedback provided to panel members following each round. RESULTS. Data saturation was achieved after round 3, with a response rate of 73.3% (n=11). The main findings suggested that student preparation prior to simulation-based learning experiences (SBLEs) should include orientation to SBLE logistics and expectations (73%), and could include informal assessment of theory (64%). Inclusion of the feedback/debriefing process (82%), methods (100%) and timing (85%) as part of student and educator preparation were also deemed essential. Panel members agreed that programme evaluation in line with stakeholder feedback (92%) is vital for guiding adjustments to the programme that is integrating simulation. CONCLUSION. The developed conceptual framework indicates the necessity of student and educator preparation to ensure optimal SBLE participation and outcome achievement. Programme sustainability should be ensured through programme evaluation and adjustment, in line with stakeholder feedback, best practice and accrediting professional body guidelines.

Many businesses in the additive manufacturing industry have limited equipment capacity. This method of using time-driven activity-based costing in collaboration with digital twinning will be advantageous to optimise their use of time and their capacity. Optimising the use of time is essential to ensure efficient process flow and to waste less time and money. To optimise, we need to analyse system dynamics and model system responses, to enable us to consider various scenarios iteratively. This paper first considers activity-based costing, driven by its most precious resource, time. Standard time is defined as the base parameter by which cost is calculated. Charge-out rates of elements are based on the actual cost of equipment apportioned to activities, based on the time spent using such equipment. The process chain is broken into elements, each of which incurs full cost when started. The value chain develops accordingly, enabling us to predict the actual cost of production. Second, the use of digital twinning to model standard time is considered. Stochastic variation is evident, but standard time can be allocated to each element in the process chain, given a certain confidence level. Together, a cause-effect prediction model can be developed. The model would predict the time that a process chain, consisting of known elements, would take. However, in the event of an occurrence out of the norm, the updated expected time can be predicted. Using the same rates, the new cost can be determined immediately. We propose that the digital twin can predict production cost, based on a statistically measurable stochastic variation of element duration and the time-varying charge-out rate.

Talle besighede in die toevoegingsvervaardiging bedryf het beperkte toerustingskapasiteit. In hierdie artikel word daar eerstens gekyk na aktiwiteitsgebaseerdekoste, met die hoof fokus op tyd. Tweedens word die gebruik van 'n digitale tweeling oorweeg om standaardtyd te modelleer. Die model voorspel die tyd wat 'n prosesketting, bestaande uit bekende elemente, sal neem. In die geval van 'n abnormale voorval, kan die opgedateerde verwagte tyd ook voorspel word. Met dieselfde tariewe kan die koste onmiddellik bepaal word. Die artikel stel voor dat die digitale tweeling die produksiekoste kan voorspel, gebaseer op staties meetbare stogastiese variasie van die duur van die element, en die tydsveranderende heffingstarief.

BACKGROUND: In South Africa, urological and other subspecialty training and exposure vary across each university at undergraduate and internship level. Many students and junior doctors complete their degrees and medical internship with little or no exposure and training to enable them to manage common urological conditions at primary healthcare level with the adequate competency, proficiency and confidence. We aimed to evaluate the exposure and urological training ofjunior doctors during internship and to determine whether it had any impact on their attitudes toward urology as a speciality in which to pursue a career. METHODS: We used a descriptive cross-sectional survey design. We emailed a questionnaire to 200 community service doctors who completed internship during 2016-2018, working across Western Cape hospitals. The questionnaire aimed to assess their clinical exposure to urology, confidence in basic urological knowledge and clinical skills, and their attitudes toward urology as a postgraduate career choice. RESULTS: The response rate was 104/200 (52%), 75% (n = 78) of the respondents had completed their internship without rotating through the urology department, 53.8% (n = 56) felt that their knowledge of essential urology topics was 'average' and still required further teaching and guidance, and 43.3% (n = 45) were not confident of performing a circumcision. 11.5% (n = 12) respondents were interested in pursuing a career in urology. The duration of the rotation through urology during internship and pursuing a career in urology were significantly associated (p = 0.005). CONCLUSION: The study showed that urological exposure and training at internship level is below the standard it needs to be in order to produce proficient and competent doctors able to practise efficiently during community service. The study also highlighted that limited exposure has a negative impact on potential future urologists wanting to pursue a career in the field. Incorporation of necessary urology skills short courses into the internship programme might help mitigate some of these challenges.

BACKGROUND: To evaluate the indications, efficacy and outcomes of endovascular renal artery embolisation (RAE) in the management of renal haemorrhage, specifically in cases of non-iatrogenic origin. METHODS: This is a retrospective case note review of 92 patients who underwent RAE in the period from August 1999 to August 2014 at Tygerberg Hospital. RESULTS: Renal artery embolisation was performed in a total of 92 patients. The indication was traumatic renal injury in 60 patients (65.2%), with mean age 28.2 years. The mechanism of injury was stabbing (55.4%), blunt trauma (7.6%) and gunshot (2.2%). Digital subtraction angiography (DSA) showed pseudo-aneurysm in 32.6%, arteriovenous fistula in 19.6% and segmental artery injury in 13%. : 85% after one, 88.9% after a second attempt, with an overall success rate of 98.3% after two attempts. In 20 of the 92 patients (mean age 50.2 years) the indication was malignancy (21.7%). Other cases included iatrogenic haematuria (4.3%) and angiomyolipoma (3.3%). Embolisation was repeated in 16.3%, with eventual success rate of 93.8%. Post-embolisation syndrome was the most common complication, seen in 9.8% of all cases. Of the 9 patients who returned for follow-up with renogram imaging, 4 had a differential function of > 20% of the embolised kidney. CONCLUSION: Renal artery embolisation remains a very successful method of managing renal haemorrhage at this hospital, whether this results from trauma, malignancy, iatrogenic or other causes.

This case is the first report of an en bloc transplantation of a horseshoe kidney in South Africa. The graft anatomy included complete fusion of the lower poles of the two kidney units with a single artery and vein associated with each unit. The thick isthmus of the graft kidney was supplied by a single, large caliber anomalous artery. Bench work (total duration 160 minutes) included the preparation of a short segment of donor aorta and IVC (containing the renal vessels) which were anastomosed to the recipient common iliac artery and common iliac vein respectively. The artery of the isthmus was anastomosed to the recipient right internal iliac artery. The graft was placed intraperitoneally. Cold ischaemia time was 15 hours, warm ischaemia time 144 minutes, total procedure time 450 minutes and estimated blood loss 1100 ml. Renogram (99mTc MAG-3) on days 1, 3 and 14 postoperatively revealed ATN. Hospital stay was 17 days and nadir creatinine at 6 weeks was 77 μmol/l.

Although many South African teachers have access to the internet, they often refrain from using available online resources to improve the quality of their own teaching. In an attempt to promote Mathematics teachers' effective use of online resources, we developed a web-based platform. This article reports on the first phase of a broader project that focuses on Mathematics teachers' perceptions about and needs for utilising technology in the classroom. Twenty-two teachers participated in this mixed-method pilot study. To obtain qualitative data, we facilitated a Participatory Reflection and Action (PRA) workshop and for the quantitative part of our study, we implemented a questionnaire. The Unified Theory of Acceptance and Use of Technology (UTAUT) were selected for the theoretical framework. With regard to effort expectancy, participating teachers found the use of technology overwhelming, resulting in a need for further training. No evidence was found of social influence affecting the participants' acceptance of technology. The participants proved to have access to sufficient equipment. However, their perceptions of their own limited skills weighed heavier than external facilitating conditions. As a result, participating teachers were hesitant to utilise technology in their teaching.

INTRODUCTION: The need for physiotherapy intervention in the treatment of mandibular condyle fractures has been highlighted in international research but no such study has been conducted in South Africa. AIMS AND OBJECTIVES: To perform a needs analysis amongst academically affiliated maxillo-facial surgeons and physiotherapists in South Africa regarding their perceived need for a post-operative physiotherapy intervention program for patients who sustained mandibular condyle fractures. DESIGN: Quantitative, non-experimental study, by means of a needs analysis questionnaire. METHODS: The questionnaire was distributed to qualified experts: one physiotherapist and one maxillo-facial surgeon from each of the South African training institutions. A convenience sampling method was used to select appropriately trained participants. RESULTS: The sample of participants was unanimous in confirming that there was a definite need for a physiotherapy intervention for mandibular condyle fracture patients whilst 85.7 % of respondents indicated that the patients should receive hospital physiotherapy. CONCLUSIONS: Experts in the field recommended that physiotherapists should provide post-operative rehabilitative therapy to patients who had sustained mandibular condyle fractures to enhance the rehabilitation process. The data obtained from the needs analysis will be applied, using the Delphi method to develop a post-operative functional exercise programme for patients who had sustained these fractures.

Many of the production costs for producing tea are attributable to the process of drying the tea. E-manufacturing can assist companies to reduce these production costs by making crucial information available to decision-makers so that they can make informed decisions. This paper presents an application of e-manufacturing to the design of an automatic tea drying control system. This control system will ensure that the multiple drying parameters such as temperature, dryer-exit tea moisture content, and fuel consumption are maintained at optimal states during the course of the drying of tea. The additional aim of this system is to balance the cost of production and the quality of the final product. Using the Guggenheim-Anderson-De Boer (GAB) model, the optimum drying temperature was found to be 100-110°C, while maintaining a dryer-exit tea moisture content of 3 to 3.12 per cent, at a drying rate of 3 per cent per minute. A Barix control application to control the system's activities, using the web user interface (WUI), was also developed.

'n Groot gedeelte van die koste in die produksie van tee is as gevolg van die tee-droogproses. E-vervaardiging kan die produksiekoste verminder deur kritiese inligting vir die besluitnemers beskikbaar te stel. Hierdie studie beskryf 'n toepassing van e-vervaardiging op die ontwerp van 'n outomatiese tee-droog beheerstelsel. Die beheerstelsel verseker dat al die droogparameters, soos temperatuur, voggehalte en brandstofverbruik, by optimum toestande beheer word deur die loop van die droogproses. Verder word daar deur die beheerstelsel 'n balans tussen die produksiekoste en die gehalte van die finale produk gehandhaaf. Deur van die Guggenheim-Anderson-De Boer (GAB) model gebruik te maak, is die optimale droogtemperatuur gevind om tussen 100 tot 110°C te lê, terwyl die droëruitlaatvoggehalte tussen 3 en 3.12% met 'n droogtempo van 3% per minuut te lê. 'n Barix beheer program is ontwikkel om die beheerstelsel se werksaamhede te monitor.

INTRODUCTION: Transrectal biopsy in suspected adenocarcinoma of the prostate (ACP) may cause significant morbidity and even mortality. A strong association between serum prostate-specific antigen (PSA) and tumour burden exists. If biopsy can be avoided in advanced disease, much morbidity and cost may be saved. OBJECTIVE: To evaluate the reliability of using PSA and clinical features to establish a non-histological diagnosis of ACP. METHODS: Androgen deprivation therapy (ADT) was used in 825 (56.2%) of 1 467 men with ACP. The diagnosis of ACP was made histologically in 607 patients (73.6%) and clinically alone in 218 (26.4%), based on a serum PSA level of >60 ng/ml, and/or clinical evidence of a T3 - T4 tumour on digital rectal examination, and/or imaging evidence of metastases. We compared two randomly selected groups treated with bilateral orchidectomy (BO) based on a clinical-only (n=90) v. histological (n=96) diagnosis of ACP. RESULTS: There was no significant difference between the groups with regard to mean follow-up (26.1 v. 26.8 months), documented PSA relapse (70% v. 67.7%), and patients alive at last follow-up (91.1% v. 95.8%). ZAR1 068 200 (US$1 = ZAR8) was saved by treating men with advanced ACP on the basis of a clinical (non-histological) diagnosis only, and a total of ZAR24 321 000 was saved by using BO instead of luteinising hormone-releasing hormone agonists as ADT. CONCLUSION: A reliable clinical (non-histological) diagnosis of advanced ACP can be made based on serum PSA and clinical features. This avoids the discomfort and potentially serious complications of biopsy and saves cost.

BACKGROUND: A visual prostate symptom score (VPSS) using pictograms was developed to assess the force of the urinary stream, urinary frequency, nocturia and quality of life (QoL). OBJECTIVE: To compare the VPSS with the international prostate symptom score (IPSS) and maximum (Qmax) and average (Qave) urinary flow rates in men from diverse language groups with limited schooling. METHODS: Men with lower urinary tract symptoms admitted to the urology ward at Windhoek Central Hospital, Namibia, were evaluated. Patients who were unable to complete the questionnaires alone were assisted by a doctor or nurse. Local ethics committee approval was obtained. Statistical analysis was performed using Student's t-test and Spearman's rank correlation test. RESULTS: One hundred men (mean age 56.3 years, range 20.1 - 95.4) were evaluated over a period of one year. All the men understood one or more of 15 languages, and 30 were illiterate; 32 had <5 years of schooling, 34 had 5 - 9 years and 34 had >9 years. The VPSS took significantly less time to complete than the IPSS. There were statistically significant correlations between the total VPSS and IPSS scores, between the four VPSS questions and the corresponding IPSS questions, and between Qmax and Qave and the VPSS total and VPSS questions on the force of the urinary stream and QoL. CONCLUSION: The VPSS pictograms depicting the force of the urinary stream and QoL correlated significantly with Qmax and Qave, indicating that they can be used as single-item questions to rapidly assess bladder outflow obstruction in men with limited education.

BACKGROUND: Changing from an open to a laparoscopic live renal donor programme poses challenges and may affect donor and graft outcomes. OBJECTIVES: To evaluate donor safety and graft outcomes for the first 50 retroperitoneoscopic live donor nephrectomies performed at Tygerberg Hospital, Cape Town, South Africa. METHODS: The procedures were performed by a single surgeon from 8 April 2008 to 3 April 2012. Operative and anatomical data were prospectively collected. A flank approach with lateral and posterior placements was used. Vascular control was achieved with Hem-o-lok clips in the majority of cases. RESULTS: The mean age of the donors was 31.5 years (range 18 - 50), 28 (56.0%) were male, and the left kidney was harvested in 28 (56.0%) of cases. The mean operating time was 149.8 minutes (range 75 - 250), mean warm ischaemic time (WIT) 181.3 seconds (107 - 630), mean blood loss 139.7 ml (5 - 700) and mean hospital stay 3.2 days (2 - 5). Mean WIT was significantly longer for right-sided than left-sided nephrectomy (213 v. 162 seconds). In two right-sided cases the renal vein was too short and vena profunda femoris was used to create length. No donor received a blood transfusion. Comparing the last 25 with the first 25 cases showed a significant decrease in mean WIT (158 v. 204 seconds, respectively) and operating time (128 v. 172 minutes, respectively). No major complications occurred. CONCLUSION: Our initial 50 retroperitoneoscopic live donor nephrectomies were performed without major complications. Donor safety was maintained during the early learning curve of the transition to minimal-access donor nephrectomy.

The Agulhas Plain is a low-lying coastal area within the Cape Floristic Region. It is heavily invaded by alien vegetation that infringes upon the sustainable supply of ecosystem goods and services provided by the native fynbos vegetation. Alien clearing and natural capital restoration is expected to recover these ecosystem goods and services and in particular to increase water availability. The study conducts cost-benefit analyses to assess whether alien clearing and natural capital restoration would add value to the Agulhas Plain through sufficiently increasing the supply of marketable ecosystem goods and services. The results indicate that the costs of alien clearing and restoration cannot be justified in the absence of water as a valued commodity. Other ecosystem goods and services included have a negligible impact on justifying costs.

OBJECTIVE: To investigate the possible reasons for repeated urethral dilatation or optical internal urethrotomy rather than urethroplasty in the treatment of male urethral strictures. PATIENTS AND METHODS: Men referred to the stricture clinic of our institution during the period April 2007 - March 2008 were reviewed and the operative urological procedures performed in the same period were analysed. Statistical analysis was performed using Student's t-test and Fisher's exact test (p<0.05 statistically significant). RESULTS: The mean age of the 125 men was 49.9 years (range 12.8 - 93.4 years). Previous stricture treatment had been given 1 - 2, 3 - 4 and 5 - 6 times in 52%, 32% and 12% of patients, respectively (4% had not undergone treatment). In these groups, previous treatment was dilatation in 70%, 76% and 72%, urethrotomy in 26%, 15% and 28%, and urethroplasty in 4%, 9% and 0, respectively. The group with 5 - 6 compared with 1 - 2 previous treatments was significantly older (mean age 60.2 v. 46.6 years) and had a significantly greater proportion with underlying co-morbidities (80% v. 52%). The group that had undergone urethroplasty compared with 5 - 6 repeated dilatations or urethrotomies was significantly younger (mean age 48.2 v. 60.2 years) with a lower prevalence of co-morbidities (47% v. 80%). During the study period urethroplasty was performed in 16 (2%) of 821 inpatients, whereas 55 men were seen who had undergone >3 previous procedures, indicating that urethroplasty was performed in less than one-third of cases in which it would have been the optimal treatment. Owing to limited theatre time, procedures indicated for malignancy, urolithiasis, renal failure and congenital anomalies were performed more often than urethroplasty. CONCLUSIONS: Factors that possibly influenced the decision to perform repeated urethrotomy or dilatation instead of urethroplasty were limited theatre time, increased patient age and the presence of underlying co-morbidities.

OBJECTIVE: We aimed to evaluate the presenting features and treatment outcome of prostate cancer in men aged <50 years, in a region where prostate specific antigen (PSA) screening is not readily available and most men present with symptoms. METHODS: We analysed the data of 1 571 men with prostatic adenocarcinoma treated between January 1997 and December 2008 at our institution, a tertiary level public sector hospital serving a largely indigent population. Statistical analysis was performed using Student's, the Mann-Whitney and Fisher's exact tests where appropriate (p<0.05 accepted as statistically significant). RESULTS: Of 1 571 men, 47 (3%) were aged <50 years. The group aged <50 years, compared with that aged >50 years, had a significantly greater proportion with poorly differentiated adenocarcinoma (53%), locally advanced (stage T3 - 4) tumours (56%), haematogenous metastases (75%), significantly higher serum PSA at diagnosis (mean 621, median 74 ng/ml) and shorter survival. CONCLUSIONS: Men aged <50 years presenting with symptoms owing to prostate cancer had significantly higher-risk disease, higher mean PSA, and poorer prognosis than men aged >50 years. To diagnose prostate cancer at a potentially curable stage in men aged <50 years, it is necessary to initiate baseline PSA testing at age 40 and 45 years, and to select high-risk men for PSA surveillance in order to diagnose potentially curable cancer in those with a life expectancy >20 - 25 years.