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One of the most prolific tornado outbreaks ever documented occurred on 26–27 April 2011 and comprised three successive episodes of tornadic convection that culminated with the development of numerous long-track, violent tornadoes over the southeastern United States during the afternoon of 27 April. This notorious afternoon supercell outbreak was preceded by two quasi-linear convective systems (hereinafter QLCS1 and QLCS2), the first of which was an anomalously severe nocturnal system that rapidly grew upscale during the previous evening. Here in Part II, we use a series of RUC 1-h forecasts and output from convection-permitting WRF-ARW simulations configured both with and without latent heat release to investigate how environmental modifications and upscale feedbacks produced by the two QLCSs contributed to the evolution and exceptional severity of this multiepisode outbreak. QLCS1 was primarily responsible for amplifying the large-scale flow pattern, inducing two upper-level jet streaks, and promoting secondary surface cyclogenesis downstream from the primary baroclinic system. Upper-level divergence markedly increased after QLCS1 developed, which yielded strong isallobaric forcing that rapidly strengthened the low-level jet (LLJ) and vertical wind shear over the warm sector and contributed to the system’s upscale growth and notable severity. Moreover, QLCS2 modified the mesoscale environment prior to the supercell outbreak by promoting the downstream formation of a pronounced upper-level jet streak, altering the midlevel jet structure, and furthering the development of a highly ageostrophic LLJ over the Southeast. Collectively, the flow modifications produced by both QLCSs contributed to the notably favorable shear profiles present during the afternoon supercell outbreak. Significance Statement The tornado outbreak that impacted the United States on 26–27 April 2011 was part of an extended outbreak that produced 343 tornadoes and numerous fatalities. This paper is Part II of a study that describes the meteorological factors supporting such a prolific event. Herein we investigate the convectively forced environmental modifications that occurred during a 36-h period encompassing three successive convective episodes. The first two episodes collectively altered the upper-level flow pattern and markedly enhanced low-level winds throughout the warm sector. These modifications served as upscale feedbacks that contributed to the first episode’s exceptional severity and to the remarkable vertical shear profiles that supported numerous long-track and violent tornadoes during the final episode on the afternoon of 27 April.

One of the most prolific tornado outbreaks ever documented occurred on 26–27 April 2011 and comprised three successive episodes of tornadic convection that primarily impacted the southeastern United States, including two quasi-linear convective systems (hereinafter QLCS1 and QLCS2) that preceded the notorious outbreak of long-track, violent tornadoes spawned by numerous supercells on the afternoon of 27 April. The ∼36-h period encompassing these three episodes was part of a longer multiday outbreak that occurred ahead of a slowly moving upper-level trough over the Rocky Mountains. Here in Part I, we detail how the environment evolved to support this extended outbreak, with particular attention given to the three successive systems that each exhibited a different morphology and severity. The amplifying upper-level trough and attendant jet streak resulted from a Rossby wave–breaking event that yielded a complex tropopause structure and supported three prominent shortwave troughs that sequentially moved into the south-central United States. QLCS1 formed ahead of the second shortwave and was accompanied by rapid flow modifications, including considerable low-level jet (LLJ) intensification. The third shortwave moved into the lee of the Rockies early on 27 April to yield destabilization behind QLCS1 and support the formation of QLCS2, which was followed by further LLJ intensification and helped to establish favorable deep-layer shear profiles over the warm sector. The afternoon supercell outbreak commenced following the movement of this shortwave into the Mississippi Valley, which was attended by a deep tropopause fold, cold front aloft, and dryline that promoted two prominent bands of tornadic supercells over the Southeast. Significance Statement The tornado outbreak that impacted the United States on 26–27 April 2011 was part of an extended outbreak that produced 343 tornadoes and numerous fatalities. This paper is Part I of a study that describes the meteorological factors supporting such a prolific event. We focus on a 36-h period encompassing three convective episodes that impacted the Southeast and culminated in the widespread formation of long-track, violent tornadoes. Flow enhancements accompanying the first two episodes and the movement of a cold front aloft into the Southeast were found to contribute to the evolution of the final and most devastating episode. Part II describes how the first two episodes directly modified the environment to enhance the severity of this outbreak.

A 50-member convection-allowing ensemble was used to examine environmental factors influencing afternoon convection initiation (CI) and subsequent severe weather on 5 April 2017 during intensive observing period (IOP) 3b of the Verification of the Origins of Rotation in Tornadoes Experiment in the Southeast (VORTEX-SE). This case produced several weak tornadoes (rated EF1 or less), and numerous reports of significant hail (diameter ≥ 2 in.; ≥~5 cm), ahead of an eastward-moving surface cold front over eastern Alabama and southern Tennessee. Both observed and simulated CI was facilitated by mesoscale lower-tropospheric ascent maximized several tens of kilometers ahead of the cold-frontal position, and the simulated mesoscale ascent was linked to surface frontogenesis in the ensemble mean. Simulated maximum 2–5 km AGL updraft helicity (UHmax) was used as a proxy for severe-weather-producing mesocyclones, and considerable variability in UHmax occurred among the ensemble members. Ensemble members with UHmax > 100 m2 s−2 had stronger mesoscale ascent than in members with UHmax < 75 m2 s−2, which facilitated timelier CI by producing greater adiabatic cooling and moisture increases above the PBL. After CI, storms in the larger UHmax members moved northeastward toward a mesoscale region with larger convective available potential energy (CAPE) than in smaller UHmax members. The CAPE differences among members were influenced by differences in the location of an antecedent mesoscale convective system, which had a thermodynamically stabilizing influence on the environment toward which storms were moving. Despite providing good overall guidance, the model ensemble overpredicted severe weather likelihoods in northeastern Alabama, where comparisons with VORTEX-SE soundings revealed a positive CAPE bias.

The maximum upward vertical velocity at the leading edge of a density current is commonly −1. Studies of the vertical velocity, however, are relatively few, in part owing to the dearth of high-spatiotemporal-resolution observations. During the Plains Elevated Convection At Night (PECAN) field project, a mobile Doppler lidar measured a maximum vertical velocity of 13 m s−1 at the leading edge of a density current created by a mesoscale convective system during the night of 15 July 2015. Two other vertically pointing instruments recorded 8 m s−1 vertical velocities at the leading edge of the density current on the same night. This study describes the structure of the density current and attempts to estimate the maximum vertical velocity at their leading edges using the following properties: the density current depth, the slope of its head, and its perturbation potential temperature. The method is then be applied to estimate the maximum vertical velocity at the leading edge of density currents using idealized numerical simulations conducted in neutral and stable atmospheres with resting base states and in neutral and stable atmospheres with vertical wind shear. After testing this method on idealized simulations, this method is then used to estimate the vertical velocity at the leading edge of density currents documented in several previous studies. It was found that the maximum vertical velocity can be estimated to within 10%–15% of the observed or simulated maximum vertical velocity and indirectly accounts for parameters including environmental wind shear and static stability.

Nocturnal mesoscale convective systems (MCSs) frequently develop over the Great Plains in the presence of a nocturnal low-level jet (LLJ), which contributes to convective maintenance by providing a source of instability, convergence, and low-level vertical wind shear. Although these nocturnal MCSs often dissipate during the morning, many persist into the following afternoon despite the cessation of the LLJ with the onset of solar heating. The environmental factors enabling the postsunrise persistence of nocturnal convection are currently not well understood. A thorough investigation into the processes supporting the longevity and daytime persistence of an MCS was conducted using routine observations, RAP analyses, and a WRF-ARW simulation. Elevated nocturnal convection developed in response to enhanced frontogenesis, which quickly grew upscale into a severe quasi-linear convective system (QLCS). The western portion of this QLCS reorganized into a bow echo with a pronounced cold pool and ultimately an organized leading-line, trailing-stratiform MCS as it moved into an increasingly unstable environment. Differential advection resulting from the interaction of the nocturnal LLJ with the topography of west Texas established considerable heterogeneity in moisture, CAPE, and CIN, which influenced the structure and evolution of the MCS. An inland-advected moisture plume significantly increased near-surface CAPE during the nighttime over central Texas, while the environment over southeastern Texas abruptly destabilized following the commencement of surface heating and downward moisture transport. The unique topography of the southern plains and the close proximity to the Gulf of Mexico provided an environment conducive to the postsunrise persistence of the organized MCS.

Micropollutants in freshwater, e.g., pharmaceuticals such as contraceptives, are a source of increased concern for human health and wildlife. Even after excretion, some of these compounds are pharmaceutically active in aquatic environment and they are found to cause endocrine disruption in both human and wildlife populations. In this study we analyzed a membrane system, coated with enzymes, which removes endocrine disrupting chemicals or micropollutants from surface water used for drinking. In order to help a membrane manufacturer in product development, we conducted a cradle-to-grave life cycle assessment. Water purification with two membrane systems, based on membrane coating covalent binding versus adsorption, were analyzed and compared with granulated activated carbon made from coal and wood. It was found that the membrane with covalent binding can have much lower environmental impacts than activated carbon made from coal. A sensitivity analysis showed that operational electricity use, the source of electricity and membrane coating frequency influence the results significantly. Scenario analysis indicates that a membrane system with covalent binding which uses operational electricity lower than 0.2 kWh per m3 of filtered water and with monthly enzyme coating frequency can perform better than conventional activated carbon systems irrespective of the electricity source. These findings can be used to guide the optimization of the membrane parameters. This study provided an understanding of the membrane modification for micropollutant removal and its impacts on environment. Finally, we describe how environmental sustainability can be integrated into business decisions, such as process and material selection and design optimization, with the help of life cycle assessment.

MBA, North-West University, Potchefstroom Campus The immense competition due to international trade is bedevilling various industrial sectors in South Africa. Numerous South African manufacturing industries are bearing the brunt of this inapt predicament. While the local consumers are privileged with significant benefits due to the increased options, the plight of many local industries such as refractory producers might not be fully understood. Therefore, it was imperative for this research study to interrogate the effects of imported refractory bricks on the operations of the local refractory brick manufacturing companies in South Africa. A detailed review of the literature established the challenges faced by refractory brick producers in South Africa due to trade, and identified the gaps in the existing body of knowledge. A critical analysis of global refractory brick trade, refractory global supply chains and competitors brought the challenges faced by local producers to the fore. The literature uncovered numerous quandaries and hurdles such as shrinking local market, reduced turnover, reduction in production throughput, closure of some refractory producers, lower employment levels and capacity utilisation. The quantitative research design approach was utilised to address the research questions and meet the objectives. A questionnaire that sought to establish the effects on the various organisational value chains was issued to a sample of 50 respondents who provided an excellent response rate of 74%. The obtained data was statistically analysed to identify the correlations imports to the various organisational value chains such as sales, market share, production output, capacity utilisation and unemployment. Negative correlations were identified between the quantity of refractory brick imports in South Africa and the operational functions of the local refractory producers such as sales, market share, production throughput, refractory job market and capacity utilisation. The findings proved that an average perceived negative effect of refractory brick imports on the operations of the local producers in South Africa was a negative 76.92 percent correlation. This negative correlation is very high and ultimately unsustainable for the local refractory brick producers. The study provided recommendations for the refractory industry, government, and the private sector, and also included recommendations for future research. Recommendations for government are anchored on the need to impose protectionist policies such as harsher import tariffs on refractory bricks in order to safeguard the industry from an impending failure and total collapse due to international trade effects. Critical recommendations for the refractory industry entailed the adoption and crafting of strategies to curb the effects of imports such as expanding into regional geographical markets in sub-Saharan Africa and the adoption of lean manufacturing principles. Masters

MBA, North-West University, Vanderbijlpark Campus The study investigating the influence of operations management decisions on overall equipment effectiveness in an engineering company. The company is based in Gauteng and 139 employees are involved in producing engineering solutions. The objective of this study was to find out what influence management decisions have on the over equipment efficiency, which currently stands at 46%, with the company improvement target set to 60%. The literature was meant to give a theoretical understanding on the following principles such the definition of OEE, factors effecting OEE such as the elements of overall equipment efficiency, the calculations for overall equipment efficiency, overall equipment effectiveness, OEE benefits, a typical form of operational decisions in any business, and the decision challenges in operations management. The population of the study design involved the manufacturing unit, which consists of 139 employees and over 20 CNC and other machines. A qualitative approach was used, and the sample was 6 CNC machines in the technical study analysis. The response rate was 33 from 139 employees. The data collection was done through a management questionnaire that was distributed in the company, and the technical data collection instrument was used to calculate the prior average OEE score. The OEE scores are from the company’s historical data (2019 -2021). The results were obtained from factors that influence operations management decisions and included and discussed in the report and recommendations will addressed in the final chapter. Masters

MBA, North-West University, Potchefstroom Campus, 2019 The study is an investigation on the impact of product quality on the performance of a tech-manufacturing company and was conducted at a manufacturing company which reported high Non-Product Conformance Costs between years 2014 — 2017. Total Quality Management is an approach of engaging in business through maximization of company's competitiveness and continually improving the quality of products and services, people and the environment. An increase in operational productivity might increase current profitability but also expose the company to risks if resources like machines and employees are over utilized. The elements of product quality are thus examined qualitatively to gain an in depth understanding of the meanings ascribed to the ratings of the components of product quality in 14 questions, five Likert scale questionnaire. A total of 14 participants were sufficient to reach the point of saturation in this study. The study concludes that the market and company performance of the company are indeed positively impacted by product quality. There is a strong relationship between the product quality and market performance. Elements of product quality such as leadership, accountability, resources, subcontractors, company culture, ownership, skills, knowledge, experience can positively or negatively impact the market and performance of a company based on the majority 5 (43%) respondents whom have worked for 10 years in the company. The impact of product quality can be reflected through growth, sustainability on the market and business profitability. Thus, manufacturing companies are recommended to pursue superior product quality as a driver of market and company performance. In addition and adoption of a bottom-up quality approach would benefit the company studied in terms of creating an organisation wide culture of quality and concern about company performance. Future studies need to apply a quantitative approach to capture a large sample and even compare two or more branches of a multinational company to understand the underlying differences in quality approaches. Masters

MBA, North-West University, Potchefstroom Campus, 2019 The study outlines the framework concerning Overall Equipment Effectiveness (OEE) using Total Productive Maintenance in the Lubrichem automated volume driven machinery. This research has been carried out using the data obtained from electronic system called RS-production of October 2016 to March 2017 at Lubrichem Company. The data were obtained through a tool for Overall Equipment Effectiveness called RS-production. The tool system (RS-production) data was from four sections or department of Lubrichem Company (Automated volume driven machines, Automated maintenance workshop, Automated blending machines and Semi-automated machines) sections. A conceptual framework was designed to determine the effect of OEE on Lubrichem automated volume driven machinery and subsequently measures availability, performance and quality losses in a system or machines. The research survey was based on the sample of four divisions of Lubrichem industry (Automated volume driven machineries, Maintenance workshop, Automated blending machines and Semi-automated machines), including analysing the outcome of the research using excel. The objective of the thesis was to identify OEE losses, downtime sources and possible improvement. The availability losses and planning factor were the highest in all four divisions. To get rid of unplanned losses, root cause analysis was performed to lower prolonging of planned change overs and setups that require Single Minutes Exchange of Dies for external (SMED) and internal events. There is a frailty relationship of the unplanned equipment losses which were grouped into unplanned production breakdowns. The losses which were recorded were identified, analysed and split into two to provide potential solutions. Some of the losses were stated as 'no reason' because production teams did not furnish the data or information. This requires awareness, training and educating of production personnel who operate the machines. Masters

MBA, North-West University, Potchefstroom Campus, 2018 Effective supplier relationship management and its impact on organizational performance is an increasingly important area of interest in the academic and the business world today. Most of the established and successful companies focus strongly on the development of closer ties with other organizations in search of competitive advantage and improved market positioning. The current literature reported trust and commitment as facilitators of long term supply chain partnerships in medical devices industry. South African healthcare has two major challenges; healthcare costs and the poor quality of the public healthcare. Both high cost and poor service can be linked to poor supply chain management. The main objective of this study was to establish whether trust and commitment influence the choice of the medical devices supplier in the South Africa. This study aims to gain insight into the factors that lead to the participants deciding to go with a specific supplier in the South African medical devices industry, paying special attention to trust and commitment. An empirical research using a questionnaire was conducted within hospitals procurement departments in Gauteng Province, South Africa. The questionnaire was developed from a literature review and contains questions and items relevant to the research problem. The finding showed that both trust and commitment have positive influence on the choice of a medical devices supplier by hospital procurement departments. However, commitment has the strongest influence of all the other constructs. The results also show that competence is vital in order to develop trust with hospitals procurement. Thus, it can be concluded that hospitals find it important to associate with suppliers that are competent and trustworthy. Further research into the operations of the South African healthcare sector is highly recommended. It is recommended that academics study vigorously the industry in order to come up with solutions to achieve envisioned better and efficient healthcare system for all South Africans. Masters