Thesis (D. Tech. (Electrical Engineering, Dept. of Process Control and Computer Systems))--Vaal University of Technology. / In recent years, industrial plant maintenance has changed dramatically. These changes are due to a considerable increase in the number and variety of physical plant assets, increased design complexity, new maintenance techniques and changing perspectives regarding on how to perform maintenance effectively. Managers at modern process plants are becoming increasingly aware of the extent to which equipment failure affects safety and the environment. Process plant personnel are limited in their ability to accurately and consistently evaluate the health of plant assets. Due to poor record keeping, maintenance staff often has little defence against aging equipment and asset failures. As a result companies have undertaken to implement planned equipment maintenance schedules and install new technology to allow for efficient tracking and analysing of equipment health across the board. The introduction of an integrated asset management solution is presented in this thesis. The integrated asset management solution will assist maintenance staff to cost-effectively predict the probability of asset failure prior to the occurrence of any actual plant incidents. The integrated solution documented in this thesis will be implemented at the Sasol Solvents site to enhance plant availability, maximum up time for all plant assets and plant safety. Strategic Asset Management Inc. (SAMI) uses the Operational Reliability Maturity Continuum model to improve profitability, efficiency and equipment reliability. The SAMI empirical model employs various stages to address improved performance and asset management and was used as a guideline to develop an integrated solution to optimise plant performance and profits. The integrated asset management solution, documented in this thesis, was developed with the intended function of bringing information from diverse plant based systems and field equipment to the maintenance personnel in an understandable interface so that the information can be used to improve the reliability and availability of all plant assets.

Made available in DSpace on 2014-07-29T15:07:47Z (GMT). No. of bitstreams: 1 Dissertacao_Alessandra_Cesar.pdf: 697265 bytes, checksum: 10184ff73bda2eae43f740e932f05ea9 (MD5) Previous issue date: 2008-12-12 / Listeria monocytogenes is a gram-positive bacterium, anaerobic facultative, that grows under refrigerator temperature and it can cause listeriosis in human and animals. It is widely distributed in the environment and it has been isolated from food of animal and vegetal origin that was associated to outbreaks of high lethality in many coutries. Thus, this bacterium represents an important pathogen to the public health. Ready-to-eat products, like cooked stuffed food, within them, frankfurters are associated to human listeriosis in many countries. Taking into consideration the importance of the subject and the need of data about it, the occurrence of Listeria spp. and L. monocytogenes in industrial plants, in meat raw materials, in slurry and frankfurters was investigated. Theses samples were harvest in this two production plants with FIS; in one of them GMP, HACCP and SOP were implemented. The results of the microbiological analysis were submitted to the program @Risk to obtain the danger analysis; the mean values results showed that 7 to 9% of the frankfurters in the market may have L. monocytogenes. After serological typification, performed by Oswaldo Cruz Institute, 88 strains of L. monocytogenes were obtained from 106 samples; among them, 76 were harvest in the industrial plants that participate in the experiment, during a day shift production and 30 were harvest in the market. In serological typification, 95% of these strains were classified as serotypes 4b, 1/2a and 1/2b. Impressions about the behavior of the population that consumes frankfurters in the matters of storage proceedings and the pattern of consumption were obtained by the application of 500 questionnaires at random. The results of these questionnaires showed that the presence of the pathogenic serotypes of L. monocytogenes in meat raw materials, as well in frankfurters commercialized by heaps, and purchased like this by about 75% of the consumers interviewed, may represent a danger to the susceptible population, especially when considering the fact of 40% of the consumers said that they eat the frankfurters directly from the package, without cooking them. Besides the consumption practices, as unknown risk factors of the presence of L. monocytogenes found in frankfurters consumed in the country, we also have lack of epidemiological data, absence of patterns as well the deficient information given to the consumer associated to the incipient relation between federal regulatory agencies and the people / Listeria monocytogenes é uma bactéria Gram-positiva, anaeróbia facultativa, que se multiplica sob temperatura de refrigeração e pode causar listeriose em humanos e outros animais. Amplamente distribuída no ambiente, tem sido isolada de alimentos de origem animal e vegetal associados a surtos de elevada letalidade em diversos países, representando, portanto um patógeno importante para a saúde pública. Produtos prontos para consumo, como embutidos cozidos, entre os quais as salsichas, estão associadas à listeriose humana em alguns países. Considerando a relevância do tema e a necessidade de dados, analisou-se a ocorrência de Listeria spp. e L. monocytogenes no ambiente industrial, nas matérias-primas cárneas, emulsões e em salsichas produzidas nesses dois estabelecimentos com SIF, sendo que em um deles as ferramentas de autocontrole estavam implantadas. Os resultados das análises microbiológicas submetidos a análise de perigos, utilizando o programa @Risk, apresenta valores médios de que 7 a 9% das salsichas destinadas ao consumo possam conter L. monocytogenes. Na sorotipificação, realizada no Instituto Oswaldo Cruz, obteve-se 88 isolados de L. monocytogenes a partir de 106 amostras, sendo 76 colhidas durante um turno de produção diurno nas indústrias que participaram do experimento e 30 no varejo, sendo 95% dos sorotipos patogênicos 4b, 1/2a e 1/2b. Noções acerca do comportamento da população consumidora de salsichas quanto aos procedimentos de estocagem e as formas de consumo praticadas foram obtidas por meio da aplicação de 500 questionários de forma aleatória, demonstrando que a presença de sorotipos patogênicos de L. monocytogenes nas matérias-primas cárneas, bem como em salsichas comercializadas a granel, adquiridas nessa apresentação por cerca de 75% dos entrevistados, oferece riscos à população susceptível, especialmente relacionando-se aos fatos de que cerca de 40% dos consumidores admitem consumir salsichas diretamente da embalagem, sem antes submetê-las ao calor. Além das práticas de consumo, como fatores do risco desconhecido da presença de L. monocytogenes em salsichas consumidas no país, ressalta-se a escassez de dados epidemiológicos, a ausência de padrãos, bem como a falta de informação ao consumidor, associada a relação incipiente entre órgãos regulamentadores e cidadãos

In this study, the goal is to optimize the process and to reduce the clogging tendency during the continuous casting process. The focus is on clogging when the refractory base material (RBM) in the SEN is in contact with the liquid steel. It is difficult or impossible to avoid non-metallic inclusions in the liquid steel, but by a selection of a good RBM in the SEN clogging can be reduced.   Different process steps were evaluated during the casting process in order to reduce the clogging tendency. First, the preheating of the SEN was studied. The results showed that the SEN can be decarburized during the preheating process. In addition, decarburization of SEN causes a larger risk for clogging. Two types of plasma coatings were implemented to protect the RBM, to prevent reactions with the RBM, and to reduce the clogging tendency. Calcium titanate (CaTiO3) mixed with yttria stabilized zirconia (YSZ) plasma coatings were tested in laboratory and pilot plant trials, for casting of aluminium-killed low-carbon steels. For casting of cerium alloyed stainless steels, YSZ plasma coatings were tested in laboratory, pilot plant and industrial trials. The results showed that the clogging tendency was reduced when implementing both coating materials.   It is also of importance to produce clean steel in order to reduce clogging. Therefore, the steel cleanliness in the tundish was studied experimentally. The result showed that inclusions originated from the slag, deoxidation products and tundish refractory and that they were present in the tundish as well as in the final steel product. / VINNOVA