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Opis: Metal stamping is a cold-forming process that uses dies and stamping presses to convert sheet metal into desired geometries. The metal stamping process leaves residues on stamped components such as releasing agents, metal shavings, and other contaminants as they exit the press. These impurities hinder the functionality of the components. Therefore, they are required to be eliminated before the stamped sheets are assembled on the production line. Contaminant metal particles on the surfaces hinder the functionality of the components and eventually promote mechanical wear between the moving parts. It is consequently difficult to eradicate contaminants, as their adhesion is inevitable, the contaminants being at a range of a few micrometres to sub-micrometres. The myriad shape configuration of the present metallic and non-metallic contaminants posed a challenge to reaching the cleanliness standards desired by the quality of the product. We aim to develop an automated decontamination process to improve product quality, with an optimized production cycle, and cost-effectiveness. Fibres non-metallic particles are also necessarily rid from the surfaces of the component. In this study, the prime focus is on metallic contaminants, excluding the non-metallic fibrous contaminants that were present. Three viable techniques are opted for based on their feasibility on production line incorporation potential. Namely, Mechanical vibration, Pressurized air-blowing, and Ultrasonic cleaning. However, to achieve the greatest possible outcome, the three different techniques are weighed against each other.
Ključne besede: Components, Ultrasonic, Vibration, Air-blow, Metallic Particles, Contamination, Technical Cleanliness, Lamination.
Objavljeno v RUNG: 26.08.2022; Ogledov: 1175; Prenosov: 45
Celotno besedilo (5,61 MB)

Opis: The available classical diagnostic methods, due to many disadvantages, do not allow effective detection of pathogenic enteric viruses in environmental samples. Due to low concentrations of pathogenic viruses in the sea, it is important to develop an effective concentration procedure for their successful detection. In the first part of the doctoral thesis, we focused primarily on the development of a protocol for an effective concentration of pathogenic enteric viruses in coastal water samples. Monolithic chromatographic columns (BIAseparations) were used for the concentration of rotaviruses and noroviruses, prior to the detection with reverse transcription quantitative PCR in real time (RT-qPCR). We tested the efficiency of concentration using columns of various chemical properties and selected pathogenic enteric viruses (rotavirus and norovirus). Among them, hydrophobic interaction monolithic column (CIM® C4) was the most effective. CIM C4 was used to optimize the concentration step and tested in waters with different salinities. The presence of concentrated viruses was confirmed by RT-qPCR and transmission electron microscope. We have developed a protocol that enables rapid concentration of viruses in coastal waters of various salinities and can be used on-site. The presence of RoV and NoV was surveyed, using the developed concentration protocol, prior to one-step RT-qPCR molecular detection, in the inner part of the Bay of Koper, in mussel farming areas and a swimming area. Rotaviruses, noroviruses and fecal indicator bacteria were frequently detected in the inner part of the Bay of Koper. Rotaviruses and noroviruses were detected in the studied area, with higher rates close to the outfall of the wastewater treatment plant in the estuary of river Rižana and were also detected in the middle of the Bay of Koper and in areas used for recreation and mussel farming. The results show that water bodies, which are otherwise defined as suitable for bathing or mussel farming, based on the results of fecal indicator bacteria, still contain low concentrations of pathogenic enteric viruses. In addition to human pathogenic enteric viruses and faecal coliforms, changes in abundance of bacteria and virus particles were studied in relation to temperature, salinity, inorganic and organic nutrient concentrations in the organically polluted Rižana estuary. Preliminary results showed spatially and seasonally changes in bacterial and viral particles abundance, and bacterial composition spatially and seasonally. However, seasonality plays a greater role in bacterial dynamics.
Ključne besede: Concentration of viruses, Enteric viruses, Rotavirus, Norovirus, Feacal coliforms, Feacal contamination, qPCR, RT-qPCR, Monolithic columns, Sewage, Seasonal dynamics, Concentration, Coastal environment, Gulf of Trieste
Objavljeno v RUNG: 02.07.2018; Ogledov: 4855; Prenosov: 211
Celotno besedilo (1,95 MB)