Stetig steigende Ansprüche an ästhetisch ansprechenden festsitzenden Zahnersatz, haben zu einer enormen Entwicklung im Bereich der enossalen Implantologie geführt. Ebenso führte die Weiterentwicklung im Bereich dentaler Keramiken zu einer immer häufigeren Anwendung vollkeramischer Systeme. In der vorliegenden in-vitro-Studie wurde der Einfluss verschiedener Reinigungsmethoden auf die Haftkraft rezementierter implantatgetragener Zirkoniumdioxid-Kronengerüste untersucht. Die untersuchten Parameter waren: manuelle Entfernung der Zementreste mit Hilfe eines Heidemann Spatels, Säuberung durch Ausstrahlung der Suprakonstruktion mit Aluminiumdioxid (Korngröße: 110 μm, 2 bar, 15s Dauer), kombinierte manuelle Säuberung und Ultraschallreinigung (Isopropanolbad 99%ig). Für den Versuch wurden insgesamt 52 Probekörper mit den drei genannten Parametern, sowie eine Kontrollgruppe mit unbehandelten Zirkoniumdioxid-Käppchen je 13 Mal einem Abzugsversuch unterzogen. Zur Herstellung der Kronengerüste wurden die Titan-Abutments mit dem Cercon® eye Scanner (DeguDent, Hanau) eingescannt und die Zirkoniumdioxid-Käppchen daraufhin digital mit der CAD-Software Cercon® art modelliert und im Labor der Firma DeguDent, Hanau, gefräst. Anschließend wurden die Kronengerüste auf den Abutments mit TempBond® NE der Firma Kerr (Ratstatt, Deutschland) zementiert und in der Universalprüfmaschine Zwick Z007 (Zwick, Ulm) den Abzugsversuchen bis zur Dezementierung unterzogen. Die Auswertung der Abzüge erfolgte mit der Software „testXpert“. Die Ergebnisse zeigten, dass die Kombination aus manueller Reinigung und Ultraschallbad verglichen mit den anderen Methoden zu statistisch signifikant höheren Retentionswerten führte. Zwischen der reinen manuellen Säuberung und der Reinigung durch Ausstrahlen des Kronengerüstes zeigte sich kein klinisch relevanter und signifikanter Unterschied.

A survey was undertaken for a contract cleaning company in Durban. In order to preserve the confidentiality of the information contained in this dissertation, a fictitious name, Kleen Co, has been used. The aim of the survey was to find further similarities within the existing segments. At present, the traditional geographic and industry-type bases of segmentation (namely healthcare, hospitality, offices and shopping centres in various regions) are used. Recent literature suggests that similarities can be sought in three areas: 1. expectations of service; 2. perceptions of service; 3. unique benefits of the service. In the survey, clients were asked to rate their expectations and perceptions for six attributes (price of the cleaning service, customer service, quality of cleaning, innovativeness of cleaning methods, assessment of cleaning requirements, and consistency of the cleaning service) . They were also asked to rate the relevance of four reasons for outsourcing (cheaper to outsource, need for specialised cleaning, company policy to outsource, and labour problems). The results indicate that price and innovation can be used as further bases for segmentation for the following segments: • offices and healthcare have the same high expectation for price; healthcare and hospitality have the same high expectation for innovation; • shopping centres and hospitality have the same low expectation for price; • offices and shopping centres have the same low expectation for innovativeness; • healthcare and hospitality have the same high perceptions for price and innovation; • offices and shopping centres have the same low perceptions for price and innovation. For outsourcing are concerned, the following reasons were found: • offices: all reasons are relevant except for price of service. • healthcare: need for specialised cleaning and labour problems are relevant; price of service and company policy are irrelevant; • shopping centres: price of service and company policy are relevant; need for specialised cleaning and labour problems are irrelevant. • hospitals: all reasons are relevant except company policy to outsource. Although the main aim of the survey was to identify new segments, client satisfaction was also measured. Clients were asked whether they had raised a complaint with the company and, if so, how satisfied they were with the outcome. This was done in order to test the loyalty of clients, the hypothesis being that the longer the client had been with Kleen Co, the more satisfied they would be with the outcome of their complaints - and more loyal. However, the data reflect that clients who have been with the company for more than four years are no more satisfied in this regard than clients who have been with the company for shorter periods of time. / Thesis (MBA)-University of Natal, Durban, 2001.

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Klagomål på damm och smuts i skolmiljöer är vanligt förekommande. Detta arbete syftar till attundersöka hur mycket deponerat damm som finns på olika ytor i skolsalar, hur en professionell städkonsulent bedömer städningen i relation till tekniska mätningar av deponerat damm, hur snabbten yta återsmutsas efter storstädning samt eventuella hälsoeffekter. Vid denna undersökning har vianvänt inomhusenkäten MM060 NA Sp1 för att fånga upp elevernas rapporterade symtom ochupplevelsen av städningen samtmätt deponerat dammmed gelfiltertjep (BM-Dustdetector). Mängden deponerat damm varierar kraftigt mellan olika skolor, sannolikt beroende på varierandepersonbelastning, lokalernas utformning samt städrutiner. Undersökningen ger visst stödför att mängden deponerat dammrelateras till upplevelsen av städkvaliteten men förhållandet bestäms ävenav många andra faktorer. Generellt uppmäts högre halter av deponerat damm på ytor som inte underhållsstädas. Storstädningen reducerar halten av deponerat damm påtagligt men återsmutsningsker snabbare där belastningen och nedsmutsningen är större. Det finns vissa samband mellan hur enprofessionell städkonsulent värderar städningen, främst golvstädningen, och uppmätta halter avdeponerat damm men sambanden är inte särskilt starka. Elever som besväras av ”damm och smuts” samt”instängd (dålig) luft” rapporterar signifikant fler symtom relaterat de icke besvärade. Exponeringför enbart besvärande damm och smuts medför en signifikant ökad frekvens av allmänsymtom, slemhinnesymtom, främst ögonbesvär, samt hudsymtom.Resultatet från denna studie pekar på att man trots alla påverkande faktorer ser en viss hälsoeffekt relativt till förekomst avdamm och smuts. Då cirka var fjärde skolelev bedöms ha någon typ av allergi är det väsentligt attskolmiljön är så ren som möjligt. Förhållandena kan sannolikt förbättras genom en ökad ochförbättrad städning / Complaints about dust in school environments are frequent. This work aims to investigate the amount of dust deposit on different horizontal surfaces in class rooms, how a professional cleaning consultant assesses cleaning in relation to measurements of dust deposit and how quickly a surfacebecomes filthy again after thorough cleaning and health effects. In this investigation we used the questionnaire MM060 NA Sp1 to estimate the students’ symptoms and experience of cleaning andmeasures deposit dust with BM-Dustdetector. The amount of dust deposit varies vastlybetweenschools probablydue to varying number of persons, the geometry of the rooms and cleaningroutines. The investigation supports the idea that the amount of dust deposit relates to the experience of the quality of cleaning but the relation is also dependent of manyother factors. Larger amounts of dust deposit are generally found on surfaces not normally cleaned. Thorough cleaning reduces considerably the dust deposit but it regrows quicklywith high loading of persons. There exist some relations between the association of the cleaning by a professional cleaning consultant, especiallycleaning of the floor, and measured amount of dust deposit but the relations are not very strong.Students complaining of “dust and dirt” and “stuffy, bad air” report significantly more symptoms than the reference group. Exposure to only “dust and dirt” gives more, general symptoms and more mucous membrane and skin symptoms. The results from this study indicate a health effect from “dust and dirt”. One out of four Swedish students have some form of allergies. It is thereforenecessary to have a clean school environment. Presumably good cleaning routines will improve the situation. / <p>ISBN 91-7997-112-1</p>

Dissolved and Colloidal substances (DisCo) and metals are released from wood during thermomechanical pulp (TMP) production. The mechanical treatment causes that these components have a tendency to accumulate in process waters, as the water circulation systems in integrated paper mills are being closed. Disturbances such as pitch depositions on the paper machine (pitch problems), specks in the paper, decreased wet and dry strength, interference with cationic process chemicals, and impaired sheet brightness and friction properties appear in the presence of DisCo substances. The presence of transition metal ions such as manganese results in higher consumption of bleaching chemicals (hydrogen peroxide) and lowers the optical quality of the final product, and addition of complexing agents, such as EDTA or DTPA, to prevent this is needed. The never ending trends to decrease water consumption and increase process efficiency in pulp and paper production stress that it is very important both to know the effects of wood substances on pulping and papermaking and to be able to remove them in an efficient way. Carried out investigations presented in this thesis show that the lipophilic extractives can be removed from TMP press water to high extent. A 90% decrease in turbidity and a 91% removal of lipophilic extractives from TMP press water can be obtained by addition of a cationic surfactant as foaming agent during flotation. Additionally, fibres located in TMP press water are not removed with the foam fraction but purified. A retained concentration of hydrophilic extractives in the process water indicates that the flotation is selective. Moreover, by introduction of a new recoverable surface active complexing agent, a chelating surfactant, manganese ions in the form of chelates can be successfully removed from the pulp fibres and separated from the process water in the same flotation process. iii The findings presented above indicate new possibilities for internal water cleaning and decreased emissions to water if flotation technology is applied in an integrated mechanical pulp mill. / ReGain/FORE

The need for industrial gas turbines to operate at higher temperatures and/or speeds has resulted in the continual modification of nickel-based superalloys to provide better high-temperature strength and corrosion resistance for components such as hot-section turbine blades. Thermal-Mechanical Fatigue (TMF) cracking, accelerated by the oxidation that forms as a result of the exposure of bare metal during the crack-opening stages, is one of the most common forms of damage experienced by service-run turbine blades. Due to the high costs associated with manufacturing nickel-based superalloy components, damaged turbine blades must be repaired to restore their original mechanical properties. One such method, Activated Diffusion Brazing (ADB), is under development for this purpose, and involves melting a two-part powder mixture into a damaged region. However, the tenacious oxides formed on nickel-based superalloy components provide an obstacle for the repair process, and must be removed. Fluoride-Ion Cleaning (FIC) uses flowing hydrogen and HF gas to remove tenacious oxide scales through a set of chemical reactions, leaving cleaned components free of oxide compounds and depleted of the strong oxide-formers of Al and Ti. GTD111 is a nickel-based superalloy containing the strong oxidizing elements of Al, Ti, and Cr, and is similar in composition to other nickel-based superalloys such as DD8 and Rene95. Literature concerning the oxidation, cleaning, and brazing of this particular alloy is limited, and as such this thesis serves as a comprehensive overview of the chemical effects of each above process on GTD111. The objectives of this project are to determine, through SEM-EDX and element mapping analysis, the oxidation behavior of nickel-based superalloy GTD111, the effects of oxidation and FIC on the chemistry near the surface of this particular alloy, and the effects of mixing ratio and paste viscosity on the quality of repairs made by ADB. Notches of 8 mm depth and 0.25 mm width were made in coupons of GTD111 via wire-EDM and samples were oxidized between 1 and 452 hours at 900°C. Samples oxidized between 96 and 452 hours were sectioned in half and one half of each sample was cleaned via the standard FIC process at Ti-Coating Inc. Notches of 8 mm depth and 1 mm width, also made via wire-EDM, were repaired by the ADB process with a bonding temperature of 1220°C and a holding time of 65 minutes. Time-dependent multi-layer oxide growth was observed on all samples, consisting of an innermost discontinuous aluminum oxide region, followed by a thin continuous band of Ni-W-Ta oxide and a thicker, very dense chromium oxide layer. Some oxidation times exhibited the presence of weak, inconsistent oxide regions rich in Ni and/or Ti. Since the GTD111 alloy does not contain sufficient amount of Al to form a continuous layer – as 5-7% Al is required – oxidation resistance was provided mainly by the formation of the dense chromium oxide layer. A region heavily depleted of Al and Ti and therefore the strengthening gamma prime phase was observed below and surrounding the Al-rich oxide regions. Chemical analysis of cleaned samples showed that the standard FIC process at Ti-Coating Inc. was able to remove all oxide compounds formed during oxidation at 900°C, and that the prior oxidation time had no effect on the chemistry within the surface of the cleaned samples; however, the depths of elemental and gamma prime phase depletion were affected. The elemental depletions of Al and Ti have been observed in past studies, but depletions of Ni and concentrations of Cr near the surfaces of cleaned components have not been previously observed. Preliminary brazing trials made with varying paste viscosities demonstrated the importance of paste pre-placement and maintaining the molten filler metal within the notch, as better pre-placement resulted in higher densities in the braze-repaired region of the brazing trial samples. Although porosity was observed on all samples, the paste pre-placement was found to be more important in reducing porosity than the mixing ratio and paste viscosity, although using an appropriate paste viscosity allowed for better pre-placement.

Surface preparation is the key factor in determining the success of a protective coating system and its ultimate objective is to create proper adhesion of a coating over an underlying substrate. Abrasive blast cleaning involves mechanical cleaning by the continuous impact of abrasive particles at high velocities on to the substrate in a jet stream of compressed air. Industries that use abrasive blasting include the shipbuilding industry, automotive industry, and other industries that involve surface preparation and painting. Materials from different origins can be used as a blasting media including coal slag, smelter slag, mineral abrasives, metallic abrasives, and synthetic abrasives. Purpose of this thesis is to investigate the usability of industrial wastes (coal slag, smelter slags, etc.) of Turkey as abrasives in surface preparation technologies. Four different slag samples of three sources, namely coal furnace slag sample from &Ccedil / ayirhan thermal power plant, ferrochrome slag sample from Eti Krom A.S., granulated blast furnace and converter slag sample from Eregli Iron and Steel Works were studied within the scope of this thesis work. The samples were prepared by crushing and screening. The chemical composition and physical characteristics of the samples were determined. All the samples were tested in industrial scale. Test results showed that the converter slag meet all the specifications for abrasives and it can be used in blast cleaning operations. However, coal furnace slag, granulated blast furnace slag and ferrochrome slag are not suitable to be used as abrasive in surface preparation technologies.

Cleaning validation of pharmaceutical manufacturing equipment is required by legislation. Generally, wet chemical techniques are employed using swabbing and/or rinse sampling methods. These are generally either selective and time consuming, or less selective and give results in a shorter period. The infrared reflection absorption spectroscopy (IRRAS) technique explored here attempts to deliver accurate, selective surface contamination information in real time to complement current methods and reduce down-time. The IRRAS instrument used in this research is a Fourier transform infrared (FTIR) spectrometer coupled by an IR fibre-optic cable to a grazing-angle sampling head with a fixed incidence angle of 80°. The introduced flexibility permits collection of in situ spectra from contaminated surfaces. Calibration models are developed using the multivariate, linear partial least squares (PLS) statistical method. The research focuses on sodium dodecyl sulfate (SDS), a model cleaning agent, on metal (aluminium and stainless steel) and dielectric (glass, EPDM and silicone) surfaces. The effects of surface finish are investigated for SDS on stainless steel. Calibrations for SDS and paracetamol in the presence of each other on glass surfaces are examined, as well as a common industrial cleaner (P3 cosa® PUR80) on polished stainless steel. For the calibration sets in this thesis, RMSECV values were < 0.41 µg cm⁻², corresponding to conservative surface residues detection limits of better than ~0.86 µg cm⁻². However, RMSECV values depend on the calibration loading range, and the detection limits were typically ~0.2 µg cm⁻² for loading ranges 0-2.5 µg cm⁻². These are below visual detection limits, generally taken to be 1-4 µg cm⁻², depending on the analyte and substrate. This shows that IRRAS is a viable method for the real-time detection and quantification of surface contamination by surfactants and active pharmaceutical ingredients on metals and dielectrics.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning). Umeå : Sveriges lantbruksUniversity. / Härtill 4 uppsatser.