A study on visual inspection of citrus sorters in a packhouse in the Eastern Cape of South Africa
- Authors: Maher, Christopher Richard
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424256 , vital:72137
- Description: Background and Purpose. The South African citrus industry is a major global producer of citrus as well as the second largest exporter of citrus fruit in the world. This industry provides employment to an estimated 112 000 workers in South Africa and is vital in providing economic opportunities to communities such as those in the Sunday’s River Valley in the Eastern Cape province of South Africa due to the low employment and education levels within this province. Citrus sorting is a visual inspection task that requires workers to sustain attention and remain vigilant for the duration of a working shift. Their role in the packhouse is to ensure that no defective products are packed for export or the local market and that the fruit meets the customers’ expectations. Since the demands of sorting citrus are poorly understood, this study attempted to assess the effect that sorting citrus has on vigilance performance as well as attempt to quantify perceived workload while taking into account different contextual factors that affect perceptions of this working task. Methods. This study was conducted within a citrus packhouse in the Eastern Cape province of South Africa. The sample was comprised of individuals employed by the packhouse as citrus sorters. In addition to a recruitment and information session, testing was conducted at three intervals during a working shift on four consecutive days. Each time, indicators of vigilance, such as correct responses, sensitivity, reaction time, false alarms and misses, were collected during a 5-minute computerised version of the Mackworth Clock-test, while perceived workload was assessed with the NASA-TLX scale, and sleepiness was recording using the WITS Sleepiness Scale. Furthermore, an open-ended question was asked to further understand factors affecting the ability of participants to concentrate during their task of sorting. Results. 18 participants consented to participate in this study. 16 of these individuals identified as female with an average age of 30 years (± 7). 83% of participants were of Black African descent and were isiXhosa speakers, while 17% of participants were of Coloured descent and Afrikaans speakers. This study found that performance, as measured by the percentage of correct responses, sensitivity and reaction time on the 5-minute long Mackworth Clock Test was not significantly affected as time-on-task for sorting citrus increased during a working shift, neither did performance on the vigilance test change as days of the week proceeded. However, ‘misses’ during the vigilance test were found to significantly decrease over the course of a working shift, thus contradicting the expected outcomes of this study. Perceived workload of sorting citrus, as well as perceived sleepiness, significantly increased with time-on-task during the course of a working shift. The major contributions for this increase in perceived workload while sorting citrus were derived from the Mental Demand and Physical Demand sub-scale for the NASA-TLX. However, responses from the open-ended question indicated that participants generally enjoyed their work, although there were factors, such as the nature of fruit and social set-up of work, that negatively affected this perception. Discussion. The results from this study contradicted the researcher’s expectations. It was anticipated that measures of correct responses and sensitivity would decrease and misses, and reaction time would increase with time-on-task for sorting citrus, yet vigilance indicators from the Mackworth Clock Test generally indicated no change in vigilance, and, according to “misses” even improved with time-on-task. A likely explanation for this is that the use of a 5-minute Mackworth Clock-test was unsuitable in this context, or rather, the time of this test was not long enough to induce a ‘vigilance decrement’. Furthermore, in order to administer this vigilance test, participants were taken off the production line and led to a testing room which most likely increased their levels of arousal, thus affecting performance on the vigilance test. However, even though perceived sleepiness was found to significantly increase over the course of a working shift, these data correlated poorly with the vigilance results, thus contradicting the expected outcomes of the study. Mental demand significantly increased, possibly due to the demand of attentional informational processing required for sorting, as well as various environmental factors present within the packhouse. Physical demand, too, significantly increased as workers were required to remain standing throughout their working task as well as to make use of their upper extremities to remove defective fruit. Correlation analyses showed significantly weak correlation for Mackworth Clock Test variables and sleepiness ratings to all other variables. NASA-TLX variables, however, generally showed significantly moderate correlations with one another. Conclusion. It remains unclear how vigilance changes and sustained attention while sorting citrus, since the experiment did not show changes in performance. This is largely attributed to the methodological set-up which could have increased arousal and therefore affected vigilance. It is recommended that future studies research vigilance and sustained attention during the sorting itself, rather than attempting to infer vigilance results from a computerised vigilance test. Perceived workload of sorting, however, increased over the course of a working shift due to significant increases in perceptions of the physical and mental demands of sorting. Future studies should address concerns relating to the physical demand of sorting. Furthermore, it would be beneficial to compare responses of day and night shift sorters to further understand how the relationship between these variables may change. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13
An investigation into fatigue prevalence amongst citrus packhouse sorters in the Eastern Cape province of South Africa
- Authors: Robinson, Harry Jack
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424312 , vital:72142
- Description: Background: South Africa is the second most influential exporter of citrus fruits internationally and holds a pivotal role in economic revenue for the country. Rural areas, such as the Sundays River Valley in the Eastern Cape province of South Africa, contribute to the country’s citrus production. Many women depend on citrus packhouses for employment as citrus sorters. As humans perceive certain defects in citrus fruits more accurately than machines, these sorters must identify and manually remove any fruit that does not conform with export requirements. Citrus sorters are exposed to numerous physical and cognitive stressors during the task while faced with organizational challenges, such as shift work and long working hours. Therefore, the potential for fatigue development is anticipated. Given the multifactorial nature of fatigue and the negative consequences it may have on workers, it also has the potential to impede the accuracy of the sorting performance. Stringent disciplinary action for the entire South African citrus industry may be of consequence if nonconforming or pest-infested fruit is missed by citrus sorters and exported to foreign countries. This study aimed to investigate the prevalence of fatigue among citrus sorters in a citrus packhouse in the Sundays River Valley of the Eastern Cape throughout a citrus harvesting season and to identify factors that may contribute towards fatigue development. Methods: The research design utilized a crosssectional, two-part approach that applied mixed methods. Part one was administered once-off, incorporating demographic, work-, and non-work-related questions. Part two was a self-developed repeated measures assessment comprising close-ended contextual questions, the Modified Fatigue Impact Scale, and the Karolinska Sleepiness Scale. Environmental and work output data were also recorded. Results: Citrus sorters (n= 35) recorded a mean MFIS score of 39.35 throughout the harvest season, which was above the prescribed fatigue threshold (38). However, there was no significant difference in fatigue ratings over time (p= 0.122). Day shift workers exceeded the fatigue threshold for the entire season compared to night shift workers, who only exceeded it in the last two weeks. The physical, cognitive, and psychosocial subscales found no significant difference in fatigue scores, although physical fatigue recorded the highest scores across all weeks and displayed a significant difference over time. Overall, participants, on average, perceived to be “neither sleepy nor alert” over the season. However, eight participants (22%) recorded sleepiness scores ii exceeding the excessive sleepiness threshold of seven. Educational levels, health status, work-pace, and the number of family dependents significantly contributed to fatigue development, albeit a weak correlation. Discussion: Sorters were perceived to be fatigued from week three till the end of the study; however, there was no variation in fatigue scores over time. An accumulation of physical fatigue over time was revealed where prolonged standing, repetitive work, and irregular working postures may have contributed. Night shift workers did not receive the recommended hours of sleep (7-8 hours); hence, they registered greater sleepiness scores over the season than day shift workers. Environmental and work output recordings did not prove to have a significant influence on fatigue development, and neither did work experience or physical exercise. Conclusion: An amalgamation of numerous contributing factors within the work situation, private situation, and the individual influenced the development of fatigue, where there was no primary causal factor. Future studies should consider recording the accuracy of the sorting performance to acquire rich, objective data. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13
Applying human factors and ergonomics system analysis methods to the V5-NRS Cessna 441 Conquest II aviation accident
- Authors: Fischer, Jordan Daena
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424245 , vital:72136
- Description: Intro: Accidents are complex in nature with multiple contributing factors. The way in which accidents are investigated is important and using system-based analysis tools assists in understanding and mapping these contributing factors to learn from them. There has been an increase in the number of accidents that have occurred within the general aviation industry in South Africa and while accident investigations have been undertaken, these have not included the application of system-based analysis tools. This led to a collaboration between Rhodes University and the Accident and Incident Investigations Division (AIID) of the South African Civil Aviation Authority where it was agreed that two systems-based analysis tools will be applied to a previously investigated accident that occurred in 2015. Aims: The first aim of this thesis was to identify if, through the implementation of these systems-based tools, the systemic contributory factors could be determined using the existing report by the AIID. The second aim of this thesis was to identify if, using the two systems-based tools, the actors and levels involved in the accident could be identified and the third aim was to identify if the implementation of these tools generates the same or different recommendations to that of the AIID. Methods: The two systems-based analysis tools applied were AcciMap and Causal Analysis using Systems Theory (CAST). These tools were applied to the V5-NRS Cessna 441 Conquest II accident report which captured the details of how the aircraft flew into the Tygerberg mountain on its descent into the Cape Town International Airport in August 2015. Results: Through the application of these two systems-based analysis tools the major contributing factors elucidated throughout this analysis were: visual and lighting conditions, pilot experience, training, lack of terrain warning equipment, fatigue, inadequate oversight, and inadequate risk management. In line with these findings, the analysis revealed various actors across various levels (the crew; South African Air Traffic Control, the SACAA, WestAir (the operator) and the Namibian Civil Aviation Authority Through the elucidation of these factors at various levels, 14 to 15 different recommendations were generated which was more than the one recommendation that was generated by the AIID. Discussion: Even when applied to an existing report, both the CAST and Accimap tools were able to bring to light the systemic contributing factors to this accident and importantly, highlight the role that various actors and levels within the system had in this unfortunate event. Consistent with previous literature, most of the contributing factors were found at the lowest level (the crew in this case) and fewer, but key factors were identified at higher levels (management and regulator level). Importantly, the application of the systems tools facilitated a systematic and systemic analysis of this accident, which allowed for the generation of recommendations at all levels, not just at the operator level. Conclusion: This study demonstrates the benefits and importance behind implementing a systems-based analysis method to an accident as these tools generate more useful recommendations which allows for important lessons to be learned following accidents, with the intention of re-designing systems to prevent them from happening again. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13
Characterizing shift systems and exploring their effects on sleep and fatigue in South African freight railway operators
- Authors: Mona, Chumani
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424300 , vital:72141
- Description: Embargoed. Expected release date 2025. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13
Development of an evidence-based framework for the prevention and management of musculoskeletal disorders in South Africa
- Authors: De Bruyn, Elrico
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424232 , vital:72135
- Description: Background: Musculoskeletal Disorders (MSDs) are multi-causal soft tissue disorders that result in disability, discomfort, and pain. MSDs are prevalent in 21.5% of the world’s population and carry a great financial and personal burden to individuals, businesses and countries alike. The multi-casual nature of MSDs has resulted in a vast amount of literature being published on how to prevent and manage the disorders, to the extent that navigating through the literature to find effective and context-specific interventions has become time-consuming and difficult. This is the case in South Africa, where ergonomists have no guide or framework to navigate MSD literature, and context-specific literature is limited. Aims: This study aimed to assist ergonomists in South Africa navigate the MSD literature to identify and select appropriate MSD prevention and management interventions. To do so, three objectives of the study were identified: 1. Review MSD literature to identify effective MSD prevention and management interventions. 2. Create a framework to act as a guide for ergonomists to navigate MSD prevention and management studies. 3. To verify the suitability of the framework in the South African context. To achieve these objectives, the study took a two-phased approach. Phase 1: A scoping review of MSD literature was conducted to identify effective MSD prevention and management approaches. Sixteen (n=16) prevention strategies and fourteen (n=14) management strategies were identified. The information from the review was analysed and grouped into five hierarchical levels of interventions (“Law”, “Organisational Policies”, “Management Systems”, Workplace Interventions”, and “Individual”). This information, along with a conceptual model created for the navigation of the literature, was used to create a draft framework for musculoskeletal disorder prevention and management. It was concluded that although there were many effective MSD interventions, there was a lack of South African-specific literature. Phase 2: Interviews with five certified ergonomists working in the South African context were conducted to verify the framework’s suitability for a South African working environment. The interviews identified two MSD prevention and three MSD management themes as effective in South Africa. Both prevention themes (“training and education” and “workplace interventions”) were also mentioned to be part of the stakeholders’ ideal MSD prevention programme, further reinforcing their usefulness. The use of “workplace interventions” was also identified to be effective in MSD management, alongside interventions at the management level and the use of alternative tools and equipment. However, the lack of managerial buy-in was identified as a barrier to MSD prevention. Stakeholders also highlighted that job specification and work hardening was an MSD strategy missing from the framework that was effective in South Africa's MSD management. The use of surveillance practices was found to be ineffective in South Africa, with lots of resistance towards it from workers. Conclusion: The framework presented in Phase 1 identified many effective MSD interventions; however, only a few were found to be applicable to the South African working context during Phase 2. Future research should focus on identifying the success of different MSD interventions in South Africa with participation from the ergonomists involved in the implementation to create an even more suitable guide that matches the South African ergonomist’s needs. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13
Quantifying the training demands of an amateur women’s Rugby union team using Global Positioning System
- Authors: Mbane, Nomabhelu
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424289 , vital:72140
- Description: Rugby union is a dynamic sport that has grown to not only be played by men but by women too. The professionalisation of the sport that happened in 1995 developed the game immeasurably including the focus given to its scientific research. This is important as literature on the demands of the game has become vital in improving the performance of Rugby union players (Deutch et al., 1998; Kay and Gill, 2004; Kruger, 2012). Scientific evidence-based data on the physical and physiological demands is imperative in the planning and setting up of training regimes (Deutch et al., 1998; Kay and Gill, 2004; Kruger, 2012). Unfortunately, the growth in the participation of women’s Rugby union has not been matched with scientific evidence-based literature that seeks to improve the performance of this population of players. Therefore, due to the unavailability of match-play during the COVID-19 outbreak, this study aimed to quantify the physical and physiological demands of training sessions of amateur women’s Rugby union players from the Sarah Baartman District, South Africa using Global Positioning System (GPS). The training’ data collected was compared to previous literature, including studies that also focused on match-play. Furthermore, players were categorized into forwards and backs, allowing for the comparison between the two playing categories. An exploratory, descriptive, observational, and comparative research design was used for the current study. The physical and physiological demands of eighteen women Rugby union players (eight forwards and ten backs) aged between 18 – 36 years old were assessed during training (for a total of nine sessions). To inform the participants’ characteristics, the players’ demographic, and anthropometric characteristics (age, stature, and body mass) were obtained. Using GPS and Zephyr technology the players’ training physical (time spent in speed zones, maximum speed, total distance travelled, number of impacts in the various impact zones) and physiological (heart rate) demands were explored. Statistical analysis methods including descriptive, independent t-test, one-way and two-way ANOVA tests were employed to analyse the data and evaluate the differences between forwards and backs. The mean age and stature for all players was 25,44±5,6 years and 1,60±0,06 m respectively, with no significant differences found between backs and forwards. With regards to body mass, forwards weighed 82,0±9,4 kg while backs weighed significantly lighter at 58,0±5,8 kg. Significant differences (p < 0,05) were found for all players in the time spent in speed zones and the number of impacts in impact zones. When all forwards’ and backs’ physical and physiological demands were compared the results showed no significant differences. The average time spent in all six speed zones combined was 11,41 and 11,62 mins for forwards and backs, respectively. The maximum speeds reached by forwards (21,35±5,72 km/h) and backs (22,85±3,88 km/h) were similar. All players combined travelled an average total distance of 2,14±0,76 km. The total number of impacts in all six impact zones, totalled 116 impacts for forwards and 97 for backs. Heart rate responses recorded for forwards and backs were 139±15 bpm and 134±13 bpm. Based on the findings of this study, the training intensity of amateur women’s Rugby union was lower than the demands experienced in the training and match-play of previous research. It was also observed that there was no specificity with regards to the training programs allocated between forwards and backs of this study. Further research on amateur women’s Rugby union is required to characterise training and match-play demands of these players. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13
Quantifying the work demands of municipal waste workers to determine physical workload and perception
- Authors: Mamabolo, Lerato
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424267 , vital:72138
- Description: Objective: This study aimed to quantify physical and perceptual workloads through the nature of the work demands of municipal waste workers. Waste workers investigated were waste collectors, street sweepers [or public cleansers], drivers and mechanics. Methods: 154 City of Tshwane municipal waste workers volunteered to participate in the study. Observation-based tools were used to measure physical workload namely, the RAMP 1 and 2, REBA and RULA, and the hand-held dynamometer was used for pushing and pulling tasks. Subjective perceptual questionnaires were used to measure Perceptual load namely the NASA TLX and the QWIQ. Results: Differences in physical workload were evident between the occupation groups. Round bin collection was the waste collection type pertaining to the highest work-related risk of musculoskeletal development. Public cleansers and flatbed truck collectors' results displayed lower task-related risks associated in relation to the other occupations. Significant differences were found between the groups, particularly between waste collectors and drivers [had high workload outputs] in relation to public cleansers [low workload] for both perceptual workload tools. A significant difference was found in the mental and physical demands, as well as the organisational constraints and quantitative workloads. Mechanics showed no significant differences between groups but had high levels of frustration. Conclusion: A relationship between physical and perceived workload intensity is evident. development of musculoskeletal diseases and injury shall incur if measures are not reinstated. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13
The ergonomic assessment of two different pipette models and their effects on biomechanical, performance, and subjective outcomes
- Authors: Masoka, Bonolo
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424278 , vital:72139
- Description: While laboratory workers are essential in many industries, they are also at a high risk of developing musculoskeletal disorders (MSDs). Manual pipetting has been identified as the leading cause of MSDs in laboratories because it exposes operators to high forces, repetition, static muscular loading, and awkward wrist postures for prolonged periods. The main contributors to the high risk associated with manual pipetting are the design of manual pipettes and how they are used. A laboratory-based study was conducted to assess and compare the biomechanical, subjective, and performance responses of an ergonomically designed pipette model to those of a traditional model. In a simulated laboratory workstation, 20 individuals performed 40 repetitions of pipetting tasks using each pipette model. Dependent variables consisted of muscle activity (of the Abductor Pollicis Brevis, Opponens Pollicis, Extensor pollicis longus, Abductor pollicis longus, Extensor pollicis brevis, and brachioradialis muscles), wrist postures, time to task completion, perceived muscular exertion (measured using the Borg RPE scale), perceived comfort and usability, and user preference. The results revealed that an ergonomic modification to pipette design has some effect on biomechanical and subjective outcomes. The ergonomic model significantly reduced muscular loading of the Opponens pollicis, and Abductor pollicis brevis muscles. The ergonomic model also reduced radial deviation and was associated with better subjective responses, while the time to task completion did not change. This study found that an ergonomic modification to pipette design can improve user comfort and well-being without compromising performance. Overall, the findings emphasize the importance of addressing pipette design to reduce the MSD risk associated with manual pipetting, and the necessity for a user-centred approach to tool design. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
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- Date Issued: 2023-10-13