Given diploma thesis deals with the design and realization of a device whose purpose is to simulate real condition in the contact area of deep groove ball bearings. Direct observation of such area was then carried out. Initial part of the thesis addresses principles occurring in ball bearings, such as friction and lubrication and wear mechanisms. Several devices which are commonly used for bearing lubrication studies are then described at the work. Subsequently, author’s solution was introduced with the output of Ball-on-ring device. Ball-on-ring configuration is key feature due to its geometry since it enables to create identical conditions as those which occur in ball bearings such as contact pressure and velocities. Lubricant distribution by the contact area is analysed with fluorescent microscopy. Part of this thesis is a validation experiment and drawing documentation of the device.

Diploma thesis was concentrated at testing of a single commercial product designed as a lipid residue removal agent, applicable in grease trap vessel. Concept was, that product is to be tested for possible content of viable microbial culture with ability to utilize various kinds of vegetable oils and animal fats, by producing functional lipase. Four types of vegetable oils were used, and two fats of animal origin: olive oil, palm oil, rapeseed oil, sunflower oil, lard and beef fat. Determined fat characteristics were: point of the saponification, the acid value, the ester value and the peroxide value. Submerged cultivation was performed on specially composed medium in which the oil or fat of choice, was mixed later. Lipolytic activity and biomass growth measurement was performed using spectrophotometry, lipid degradation ability was measured using titrimetry. Based on results it can be stated that tested microorganisms, originated from product, and its lipase has ability to successfully utilize all of used fats and oils and thus, theoretically, remove its content from grease trap.

Submitted master’s thesis is focused on the study of possibilities of lipids degradation in particular wastewaters originating in food industry or restaurants. The effort is given to the employment of lipolytic activity presenting microorganisms. In the literature review, wastewater treatment with aim on the sludge management and fat separators are described, as a way how to pre-treat these wastewaters. In this part the enzymes lipases of microbial origin are researched from point of view of their production conditions and possible applications. The experimental part is dedicated to the research of optimization of cultivation conditions for lipases production employing selected microorganisms (Bacillus subtilis, Geobacillus thermodenitrificans, G. thermocatenulatus and mixed bacterial culture Thermus and Bacillus) and a commercial formulation (Sany Duo Spezial). Lipases production and growth of microorganisms are determined spectrofotometrically on various concentrations of lipids. Moreover, employing the solid nutrition medium, the effect of detergents onto the Bacillus subtilis culture was assessed, since detergents are generally abundant in this particular wastewaters. As a conclusion, vide supra mentioned microorganisms were characterized according to their abilities to degrade triacylglycerols.

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La grande diversité des applications, dans tous les domaines industriels, des plus simples aux plus complexes, que ce soit pour un usage quotidienne ou pour des applications high-tech, nécessite la conception continue de systèmes d'étanchéité de plus en plus performants. Les vérins pneumatiques sont des éléments fondamentaux de l'automatisation dans des domaines industriels très variés : les dispositifs de levage, la robotique, l'aérospatial, les systèmes respiratoire, etc. Cependant, un dysfonctionnement d'étanchéité conduit à des performances plus faibles et même à des disfonctionnements. Inversement, une meilleure connaissance des phénomènes aux interfaces, permettra l’amélioration du rendement, la prolongation de la durée de vie et de la fiabilité des différentes applications pneumatiques.Ce travail de thèse est focalisé sur l'étude expérimentale et numérique des systèmes d'étanchéité par joints pneumatiques. Un banc d'essais modulable a été conçu et réalisé pour permettre l'investigation expérimentale de différents types de joints pneumatiques, pour une large gamme de conditions de fonctionnement, en termes de vitesse linéaire, pression pneumatique et solutions constructives. Il permet principalement de caractériser le frottement des joints mais aussi la visualisation des phénomènes physiques au niveau de la zone d'étanchéité et de son environnement.En parallèle, un modèle théorique ElastoHydroDynamique, incluant la prise en compte des conditions de lubrification mixte et le comportement rhéologique non-newtonien de lubrifiant (graisse) a été développé. Il est basé sur le couplage d'un logiciel de calcul non-linéaire (permettant la prise en compte du comportement mécanique hyperélastique des joints) et un modèle d'écoulement en film mince. Les comparaisons de mesures expérimentales avec les prédictions numériques ont permis de valider le modèle théorique ainsi que d'améliorer la compréhension des conditions de fonctionnement et d'alimentation de la zone d'étanchéité. / The great diversity of applications in all industrial fields, from the simplest to the most complex, whether for everyday use or for high-tech applications, requires the continuous design of increasingly efficient sealing systems. Pneumatic cylinders are fundamental elements of automation in a wide variety of industrial fields: lifting devices, robotics, aerospace, respiratory systems, etc. However, a sealing failure leads to lower performance and even malfunctions. Conversely, a better knowledge of the phenomena at the interfaces will allow the improvement of efficiency, the extension of the service life and of the reliability of the various pneumatic applications.This thesis work focuses on the experimental and numerical study of pneumatic seal systems. A modular test bench has been designed and built to allow the experimental investigation of different types of pneumatic seals, for a wide range of operating conditions, in terms of linear velocity, pneumatic pressure and constructive solutions. It mainly allows to characterize the friction of the joints but also the visualization of physical phenomena at the level of the sealing zone and its environment.In parallel, an ElastoHydroDynamic theoretical model, including the consideration of mixed lubrication conditions and the non-Newtonian rheological behaviour of lubricant (grease) has been developed. It is based on the coupling of a non-linear comercial software (allowing the modelling of the hyperelastic mechanical behaviour of the joints) and a thin film flow model. Comparisons of experimental measurements with numerical predictions validated the theoretical model and improved the understanding of the operating and supply conditions of the sealing area.

<p>Uppsatsen beskriver tiden kring 50-talet för att genom detta visa den ungdomskultur som då uppstod. När filmen Ung rebell hade premiär 1955 var den en föregångare inom filmbranchen genom att gestalta ungdomskulturen på ett nytt sätt. Uppstasen analyserar denna film, Sista natten med gänget (1973), samt Grease (1978) för att visa vilka verktyg som används för att visa ungdomskulturen under denna tid. En del av analysen är att påvisa bilens roll i ungdomskulturen i film gesaltad under och strax efter 50-talet.</p>

Målet med detta arbete är att undersöka smörjsystemet på två utsatta leder på en Boomer E2C. Förfrågan om examensarbetet kommer från Atlas Copco Rock Drills AB i Örebro som också tillverkar maskinen. Atlas Copco Rock Drills AB har idag ett fettsmörjningssystem som upprätthåller funktionerna på lederna. Uppgiften är att sammanfatta och utvärdera dagens system samt att finna nya lösningsförslag som skulle kunna ersätta eller delvis ersätta systemet. Information har hämtats från dokumentation, ritningar och samtal med konstruktörer på företaget. Efter att alla förutsättningarna för lederna specificerats så har lösningsförslag sökts. Genom att träffa lagerleverantörer och söka artiklar så har idéer formats. Brainstorming har använts för att kunna se nya lösningar. Undersökningen har visat att det finns problem med dagens lösning vad gäller slanghaverier och driftstopp i fält. Atlas Copco AB uttrycker även att kunskapen och dokumentationen angående systemet är otillräckligt. Efter artikelsökning så kan konstateras att forskningen och kunskapen på området med tungt belastade, oscillerande och fettsmörjda leder är liten. Dimensionering sker ofta med hjälp av erfarenhet och med tankesättet ”det har fungerat förut”. När lösningsförslagen har jämförts så har detta gjorts genom att använda metoden AHP (Analytic Hierachy Process). Med denna metod så jämför man kriterierna från kravspecifikationen med lösningsförslag så att man matematiskt kan räkna fram ett vinnande lösningsförslag. Resultatet visar att en smörjfri lösning skulle teoretiskt vara att föredra. Denna skulle tillverkas av en modern polymer och kompletteras med en inre tätning och ett yttre skydd. Atlas Copco rekommenderas att testa de olika förslagen för att komma fram till vilken som är bäst lämpad för applikationen. / The goal of this work is to investigate the lubrication system on two exposed joints on a Boomer E2C. The request for the thesis comes from Atlas Copco Rock Drills AB, Örebro, which also manufactures the machine. Today Atlas Copco Rock Drills AB has a grease lubrication system that secures the function of the joints. The task is to summarize and evaluate the current systems and to find new solutions that would be able to replace or partially replace the current system. Information was gathered from documents, construction drawings and conversations with engineers at the company. Solutions and ideas have been formed by meeting stock suppliers and searching for articles. Brainstorming has been used in order to find new solutions. The investigation has shown that there are problems with the current solution in terms of hose failures and downtime in the field. Atlas Copco AB also expresses that there is a lack of documentation and knowledge regarding the lubrication system. After the various article searches it became clear that research and knowledge in the area with heavy duty, oscillating and grease lubricated joints is insufficient. The design is often done with the help of experience and with the mindset "it has worked before." When the solutions and ideas have been compared, this has been done by using AHP (Analytic Hierarchy Process). This method compares the criteria that must be fulfilled by the solutions and then calculates the best one. The results show that a lubrication-free solution would theoretically be preferable. This would be produced by a modern polymer and supplemented with an inner seal and an outer protection. Atlas Copco is recommended to test the various proposals to be able to decide which the best solution for the application is.

Paper and cellulosic materials hold a good promise of being candidates for flexible packaging materials provided suitable barrier properties such as water repellence and grease resistance are imparted to them. One of the methods to achieve these objectives is to surface modify paper/cellulose by applying thin fluorocarbon coatings on the surface. Fluorocarbon thin films produced by plasma enhanced chemical vapor deposition (PECVD) offer several advantages over the films produced by conventional polymerization means. Plasma deposited films are pinhole-free, chemically inert, insoluble, mechanically tough, thermally stable and highly coherent and adherent to variety of substrates. In this work, we investigate the use of PECVD technique to produce barrier films on paper and cellulosic materials. These films, with composition and properties not much different from PTFE, repel water and act as a good barrier to lipophilic materials. Two different monomers, pentafluoroethane (PFE; CF3CHF2) and octafluorocyclobutane (OFCB; C4F8), were investigated and compared in terms of deposition rates and final film properties. Various analytical techniques (XPS, FT-IR, SEM, Ellipsometry, Contact Angle Goniometry, etc.) were used to characterize the fluorocarbon films. The fluorocarbon coated paper exhibited hydrophobic character as evidenced by high water contact angles. Although the films allow water vapor diffusion, the films are hydrophobic and are not wetted when liquid water contacts these layers. Based on various thickness of these films deposited on surface of cellulose, there was a minimum PFE film thickness required to achieve a stable hydrophobic behavior. The fluorocarbon films investigated in this work also exhibited good resistance to lipophilic materials (e.g. oils, fatty acids, etc.). While techniques such as oleic acid penetration and TAPPI "oil-kit" test are commonly used in paper industry to qualitatively test the grease barrier properties of paper/cellulose, this work attempts to quantify the grease barrier properties of fluorocarbon coated paper using techniques such as magnetic resonance imaging (MRI) and quartz crystal microbalance (QCM). Finally, the feasibility of deposition of dual layer films by PECVD was investigated using PFE and n-isopropylacrylamide (NIPAAM) as precursors for applications in barrier packaging and printing.

The utilisation of waste process grease (WPG) as feedstock for biodiesel production was investigated in this study. WPG is a lubrication oil used in the metalworking industry and is considered a hazardous waste material. WPG contains vegetable oil and animal fat which are used as base oils in the lubricant formulation. Three different production routes were followed to produce biodiesel using WPG as feedstock. The first production route involved the conventional two-step production process comprising the acid esterification of the free fatty acids, followed by alkaline transesterification. The second production route involved the extraction of free fatty acids in the WPG by means of liquid-liquid extraction and the production of biodiesel from the extracted free fatty acids through acid esterification. The produced biodiesel was purified by means of chromatography. A third process route was the saponification of the WPG using aqueous sodium hydroxide followed by acidulation with hydrochloric acid. The resulting acid oil was purified by means of column chromatography, using a hydrophobic resin as the stationary phase prior to esterification through acid catalysis to produce biodiesel. The crude biodiesel was purified using column chromatography with silica gel as stationary phase. The optimum reaction conditions for the reduction of the free fatty acid content of WPG in route 1 to 0.5% were a methanol to oil ratio of 8:1 and a reaction temperature of 65 °C with a catalyst loading of 4 wt%. Acetonitrile was found to be the most effective extraction solvent for the reduction of sulphur compounds in the free fatty acid feedstock in route 2. A reverse phase chromatographic system with a hydrophobic stationary phase and methanol as the mobile phase was found to be an effective system to reduce the sulphur to below 10 ppm as specified by the SANS 1935 biodiesel standard in route 3. Both the conventional two-step process (route 1) and the liquid-liquid extraction process (route 2) were found not to be suitable for the production of biodiesel from WPG as the sulphur content of the produced biodiesel for routes 1 and 2 was 8 141 ppm and 4 888 ppm, respectively. The sulphur content of the produced biodiesel following route 3 was 9 ppm. The latter approach reduced the sulphur content of the biodiesel to acceptable levels that conform to the SANS 1935 standard to be used in a B10 biodiesel blend. A biodiesel yield of 45%, calculated as the mass of biodiesel produced as a percentage of the total mass of dried WPG used, was achieved with route 3. The biodiesel conformed to most of the specifications in the SANS1935 standard for biodiesel. The presence of a relatively high concentration of saturated fatty acids reflected in the higher cetane number of 74.7, the high cold filter plugging point of +10 and the oxidative stability of > 6 hours. A comparative cost analysis for route 3 indicated that the production cost of biodiesel, compared to the cost of petroleum diesel is marginally higher at the current Brent crude oil price of $102.41 per barrel. The production of biodiesel from WPG will be economically viable once the crude oil price has risen to about $113 per barrel. / Thesis (PhD (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.