M. Tech. (Department of Mechanical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / The subject of maintenance optimisation is not new, and many researchers have explored it. However, it is seen that one optimisation solution cannot be used in all industries. Each industry and equipment thereof are unique as the product streams differ, layouts and operation variables, to name a few. Though Turn-around management is the most used strategy in petrochemical industries. Equipment downtime remains the biggest challenge thus, the purpose of the study was to optimise the maintenance practices used on the critical electromechanical equipment in Sasol Synfuels Catalyst Preparation using both the Analytical Network and Analytical Hierarchy multi-decision approach. Data was collected from the SAP system database, of which the breakdown work orders was obtained from the period of January 2016 to June 2021. The data was collected for each 13 electromechanical equipment identified in the catalyst preparation unit. The applied maintenance strategies employed on the electromechanical equipment in the catalyst preparation unit was also analysed using the Meridium maintenance strategy software tool utilised in Sasol Synfuels. An analysis and identification of the critical equipment within the unit were obtained with the use of two different methods, namely the JADERI, (2019) and AFEFY, (2010) approaches. A theoretical distribution was drawn after that in order to assess the effectiveness of the current maintenance strategy compared to the identified key performance indicators. The theoretical distribution analysis was used to determine the plant utilisation, availability, and maintenance cost. The analytical network and hierarchy process application, and the super decision network model framework, were analysed to obtain the maintenance optimisation solution. Though the ANP and AHP approaches have different problem identification frameworks and cluster dependencies, it is seen that both methods portray more or less similar results. Both methods indicate that in order to achieve an optimised maintenance strategy within the catalyst preparation unit, condition-based maintenance strategy is the most weighed alternative node with 50% for optimal maintenance solution. The least most weighed alternative node is corrective maintenance, weighed at 7%. This is true as corrective maintenance is applied once a breakdown has occurred, of which the aim is to avoid unforeseen breakdowns. Fixed time maintenance is the second most weighed maintenance strategy with 30%, followed then by the operate to failure strategy at 13%. Considering that the operation to failure maintenance strategy is applied based on the consequence of failure and maintenance cost as well as mean time to repair, this is then concluded as practical as RCM priorities predictive and preventative strategies to be employed. It was drawn, for criteria nodes, that the ANP approach resulted in the environmental safety impact as the most important criteria to consider when applying the optimal maintenance strategy in the Sasol Synfuels Catalyst preparation unit. The environmental safety impact was rated at 0.33, followed by availability with a factor of 0.32. The least weighed criteria nodes are then the maintenance cost and MTTR, both with a factor of 0.17. This proves to true considering that the petrochemical industry is considered a high-risk industry as it processes and produces hazardous chemicals The AHP approach structure however, does not consider interdependencies through the criteria and alternative clusters thus the alternative weight could not be defined. The results obtained prove that the ANP approach is the most practical mutli criteria decision making method for maintenance optimisation compared to the AHP approach.

Bakgrund: På en operationsavdelning används en betydande mängd medicintekniskutrustning. Anestesisjuksköterskor, operationssjuksköterskor och undersköterskoransvarar för att förbereda, iordningställa och hantera maskiner, utrustning och detmaterial som behövs under en operation eller undersökning. För att kunna utföraarbetet behövs kunskap och samarbete. Den medicintekniska utrustningen byts ut,uppdateras eller ersätts för att förbättra och/eller effektivisera i det område den äravsedd att användas. Motiv: Mängden medicinteknisk utrustning ökar och den uppdateras eller byts utmot mer avancerad utrustning. Det kräver att operationspersonalen ständigtuppdaterar sina kunskaper. Ofta förväntas personalen att ta till sig ny utrustningunder pågående operationsprogram mellan operationer. Syfte: Att beskriva operationspersonalens erfarenheter av att arbeta medmedicinteknisk utrustning. Metod: För att undersöka personalens erfarenheter av att arbeta medmedicinteknisk utrustning valdes en kvalitativ metod med semistruktureradeintervjuer. Nio intervjuer analyserades med innehållsanalys. Resultat: Presenteras i två kategorier med underliggande subkategorier: Positivaerfarenheter av medicinteknisk utrustning. Med subkategorierna; Denmedicintekniska utrustningen fyller ett syfte, Den medicintekniska utrustningenfrämjar patientsäkerheten och Kunskap och erfarenhet påverkar arbetet medmedicinteknisk utrustning positivt. Negativa erfarenheter av medicintekniskutrustning. Med subkategorierna; Den medicintekniska utrustningen innebärtidskrävande arbete, Den medicintekniska utrustningens påverkan på arbetsmiljön,Bristande utbildning om medicinteknisk utrustning och Den medicintekniskautrustningens påverkan på patientsäkerheten. Det mest framträdande resultatet varatt samtliga deltagare uttryckte att det läggs för lite tid och resurser till utbildning. Konklusion: Om utbildning prioriteras skulle det kunna minska stress, irritation,förkorta operationstider, ge mer tid till patienterna och förbättra patientsäkerheten. / Background: In the surgical ward a substantial amount of medical equipmentis used. The anesthetic nurses, operating theatre nurses and the assistant nursesare all responsible for setting up and preparing the appropriate machines, equipment and material as well as knowing how to use them. In orderto accomplish this both teamwork and knowledge is needed. In order to enhanceand or increase efficiency medical equipment is updated or replaced. Motive: The amount of medical equipment increases in a steady state, isupdated or replaced with more advanced equipment thus the staff in theoperating ward constantly needs to keep updating their knowledge. Staff areexpected to learn how to handle new equipment in between operations andduring ongoing operating schedule. Aim: The focus of this study was to describe the staff¨s experiences of workingwith medical equipment. Methods: A qualitative method with semi structured interviews was used. Nineinterviews were analyzed with a content analysis. Result: Two main categories with subcategories. Positive experiences ofworking with medical equipment. Subcategories: The medical equipmenthas a purpose, Medical equipment enhances patient safety and Knowledge andexperience affects work with medical equipment in a positive way. Category:Negative experiences of working with medical equipment.Subcategories: Working with medical equipment is time consuming, Themedical equipment’s impact on the working environment, Lack of education ofthe medical equipment and Medical equipment affect´s patient safety. The mostprominent result was that all the informants experienced lack of opportunities toachieve correct education of the medical equipment. Conclusion: Prioritization of education and training could reduce stress,irritation, shorten operating time, create more time to take care of patients andenhance patient safety.

Pollution from nonpoint sources is a leading cause of receiving water quality impairment. The largest source of nonpoint pollution is storm water runoff, which includes pollutants such as sediment, nutrients, metals, microorganisms, and organic compounds. Sediment is of particular importance because many pollutants are readily 5 adsorbed onto particles. In the Lake Tahoe basin, sediment is also significant because of its direct contribution to clarity attenuation. The most prudent control measure for mitigating sediment flux in the Lake Tahoe basin is infiltration, which captures runoff volume, allowing it to percolate into the soil and enter groundwater. All residential parcels in the Lake Tahoe basin are required to have an on-site infiltration system. These systems require rigorous maintenance to maintain full function. Negligence can lead to premature clogging from debris and accumulated sediment, and the cost of rehabilitating or replacing the system can be significant to homeowners. It is mandatory for a sediment trapping device to be installed to pretreat runoff discharged into the infiltration system; however, there is limited infomation regarding sediment trapping devices designed for residential use. The objective of this research was to evaluate the performance of an on-site stormwater treatment device in removing sediment from simulated stormwater runoff. The sediment trapping device consists of removable, porous 200-micron nylon inserts for filtration and is designed to mitigate premature clogging infiltrative runoff control measures. Laboratory analysis of a full scale device model was performed. Removal efficiency, effluent concentration, and bulk solids removal were assessed for perfomance evaluation. The device demonstrated a median removal efficiency from grab samples of 74%, median total suspended solids effluent concentration of 72 mg/L, and removed 89% of the total solids introduced into the system. Economic and sustainability implications of the device were also assessed.

Background: Cyclotrons form a central infrastructure and are a resource of medical radionuclides for the development of new radiotracers as well as the production and supply of clinically established radiopharmaceuticals for patient care in nuclear medicine. Aim: To provide an updated overview of the number and characteristics of cyclotrons that are currently in use within radiopharmaceutical sciences and for the development of radiopharmaceuticals to be used for patient care in Nuclear Medicine in Germany (D), Austria (A) and Switzerland (CH). Methods: Publicly available information on the cyclotron infrastructure was (i) consolidated and updated, (ii) supplemented by selective desktop research and, last but not least, (iii) validated by members of the committee of the academic “Working Group Radiochemistry and Radiopharmacy” (AGRR), consisting of radiochemists and radiopharmacists of the D-A-CH countries and belonging to the German Society of Nuclear Medicine (DGN), as well as the Radiopharmaceuticals Committee of the DGN. Results: In total, 42 cyclotrons were identified that are currently being operated for medical radionuclide production for imaging and therapy in Nuclear Medicine clinics, 32 of them in Germany, 4 in Austria and 6 in Switzerland. Two thirds of the cyclotrons reported (67%) are operated by universities, university hospitals or research institutions close to a university hospital, less by/in cooperation with industrial partners (29%) or a non-academic clinic/ PET-center (5%). Most of the cyclotrons (88%) are running with up to 18 MeV proton beams, which is sufficient for the production of the currently most common cyclotron-based radionuclides for PET imaging. Discussion: The data presented provide an academically-updated overview of the medical cyclotrons operated for the production of radiopharmaceuticals and their use in Nuclear Medicine in the D-A-CH countries. In this context, we discuss current developments and trends with a view to the cyclotron infrastructure in these countries, with a specific focus on organizational aspects.

The effects of the Federal Communications Commission Registration Program of 1977 on the structure of the domestic telecommunications equipment producing industry was evaluated. Econometric analysis and anecdotal evidence were used as the foundation for the investigation. The major hypothesis of the paper was that the FCC Registration Program of 1977 changed the structure of the telecommunications equipment producing industry from a monopoly to an industry characterized by competition. This resulted in a change in the equilibrium price and output in the market place with price decreasing and output increasing. The three major component subsectors, i.e., transmission equipment, switching equipment, and customer premises equipment (CPE) were discussed individually and collectively to determine any differential effects. This was particularly relevant because the FCC Registration Program focussed on CPE. Empirically, the central hypothesis was supported. Also, differential effects in the various subsectors were found. / M.A.

Two instruments mounted in a piggyback arrangement were developed for time-resolved measurements of dynamic flow quality in a transonic cryogenic wind tunnel. The first one is a dual hot-wire aspirating probe for measurement of stagnation pressure and temperature. The second is a miniature high-frequency response angle probe consisting of surface mounted pressure sensors. The aspirating probe was tested in the 0.3-m Transonic Cryogenic Tunnel (TCT) at NASA-Langley Research Center. Stagnation pressure and temperature measurements were taken in the free-stream of the settling chamber and test section. Data were also obtained in the unsteady wake shed from an airfoil oscillating at 5 Hz. The investigation revealed the presence of large stagnation pressure and temperature fluctuations in the settling chamber occurring at the blade passing frequency of the tunnel driving fan. The fluctuations in the test section are of a much more random nature and have amplitudes much lower than those in the test section. The overall results are consistent with previous tunnel disturbance measurements in the 0.3-m TCT. In the unsteady wake shed from the oscillating airfoil, stagnation temperature fluctuations as high as 42 K rms were observed. The high-frequency angle probe is a four sensor, pyramid type probe capable of simultaneously measuring time resolved stagnation and static pressures and two orthogonal flow angles. Using measurements from both probes, all flow parameters of interest can be deduced. Aerodynamic behavior of a full size model of the probe was established in an open air jet of known conditions. / M.S.

The objectives of this research were to modify and test a prototype sawdust dryer designed by Arrowhead Forest Products and a sawdust-fueled suspension burner developed at Virginia Tech. The dryer was designed to process green sawdust at small to medium-sized sawmills and pallet mills. The sawdust burner was designed to be the heat source for the dryer and serve more general needs. A series of trials were conducted to develop the operating parameters of the dryer and measure the dryer's effectiveness at reducing moisture content to 0%. Separate tests were conducted on the burner to determine maximum heat outputs and combustor efficiencies using sawdust fuel of various moisture contents and particle sizes. The sawdust dryer proved capable of reducing the moisture content to 0% after several passes through the system. The sawdust burner produced close to 400,000 BTU's/HR at calculated efficiencies over 90% and proved relatively insensitive to ranges of fuel moisture contents and particle sizes. / Master of Science

This thesis describes the work done on the first phase of the implementation of an Automatic Passenger Counting (APC) system at the Roanoke Valley-Metro transit property. The primary objective of the first phase of this project was to create a software program to decode, edit, analyze and store the data from the APC. The second phase of the project will make reports by aggregating data from the work done in the first phase. The basis for efficient management of operations in transit properties is having accurate and reliable information on transit ridership, fare revenue, and schedule adherence for individual routes and for the transit system as a whole. Data from passenger counts are used to identify peak load points and quantify service demands. Fare revenue data are needed to analyze the systems productivity, and the time checks are essential to monitor and control the scheduling activities. The actual data collection efforts at Valley-Metro have proven to be obsolete, unreliable and very expensive. The new APC system offers the management at Valley-Metro with a new and powerful tool that will enhance their capability to make better decisions when allocating the service needs. / M.S.

The research reported here explored, a "new" approach to biomass energy conversion for small-scale process heat-applications. The conversion process uses close-coupled catalytic. combustion to burn combustibles in effluent generated by primary combustion or gasification of biomass fuels. Computer control of primary and secondary air flow rates allow control of the devices output power while maintaining fuel-lean or stoichiometric conditions in the effluent entering the catalytic combustion zone. The intent of the secondary combustion system is to ensure "clean" exhaust (i.e., promote complete combustion). A small-scale combustor/gasifier was built and instrumented. Characteristics of combustion were studied for three biomass fuels so that primary and secondary air flow control strategies could be devised. A bang-bang type controller was devised for primary air flow control. Secondary air as controlled based on feedback signals from an inexpensive automobile exhaust gas oxygen sensor. The control strategies and catalytic combustion were implemented on prototype combustor/gasifier and the device was tested with good results. Power turn down ratios of 4 to 1 and 3 to 1 were achieved. The zitconia-type automobile exhaust gas oxygen sensors adapted well to the combustion environment of biomass fuel, at least for short periods (long term durability tests were not conducted). The secondary air control system was able to maintain fuel-lean flows for the most part and, the secondary combustion system provided reductions of approximately three fourths in carbon monoxide emissions. / Master of Science

The static cone penetrometer is an in-situ testing tool which was originally developed to derive information on soil type and soil strength. More recently, it has found application in liquefaction assessment. Typical cone penetrometers are heavy duty devices which are operated with the assistance of a drill rig. However, this capacity is not necessary in the case of field studies of liquefaction, since liquefaction usually occurs at relatively shallow depths. This thesis is directed to the goal of the development of a miniature, lightweight cone penetrometer which can be used in earthquake reconnaissance studies related to liquefaction problems. The research for this thesis involved four principal objectives: 1. Development of procedures to automatically acquire and process measurements from a miniature electrical cone; 2. Develop and perform tests in a model soil-filled bin to calibrate the cone; 3. Evaluate the utility and accuracy of the cone results as a means to assess conventional soil properties; and, 4. Conduct a preliminary evaluation of the cone results in the context of recently developed methods to predict liquefaction potential. The work in regard to the first objective involved assembling and writing software for a microcomputer based data acquisition system. Successful implementation of this system allowed data from the tests to be rapidly processed and displayed. Calibration tests with the cone were carried out in a four foot high model bin which was filled ten times with sand formed to variety of densities. The sand used is Monterey No. 0/30, a standard material with well known behavioral characteristics under static and dynamic loading. The test results showed the cone to produce consistent data, and to be able to readily distinguish the varying density configurations of the sand. Using the results in conventional methods for converting cone data into soil parameters yielded values which were consistent with those expected. Liquefaction potential predictions were less satisfying, although not unreasonable. Further research is needed in this area both to check the reliability of the prediction procedures and the ability to achieve the desired objectives. / M.S.