This dissertation aims to contribute to the discourse on the future of manufacturing in Sweden. It is argued that the real threat does not come from lower wages in Eastern Europe and Asia. Rather it comes from an inability to make the most of existing manufacturing systems. The joint contribution of the underlying studies that this dissertation is based on provides compelling support for corroborating this line of thought. More important, however, is that in addition to showing that there is room for improvement, a lot of input is provided on how to act creatively for enhanced performance. The discussion on how to act mainly focuses on three research issues. First, enhancing continuous improvement capability. The continuous improvement abilities considered most important for Swedish manufacturers to develop are pointed out. That is, the ability to adopt a systematic and strategic approach to continuous improvements, the ability to lead the way towards continuous improvements, and finally the ability to involve customers and suppliers in continuous improvements. Furthermore, the likely positive performance impact of accomplishing this is clarified. Second, adopting the principles of lean manufacturing. Rather than reinforcing Taylorism, it is shown that lean manufacturing seems to contribute to the creation of sustainable work systems in Sweden. However, a broad process of change awaits the many companies that might aspire to transform their operations in this direction. In order to reap the full potential of this strategy, the work organisation, as well as management accounting and remuneration systems, must change, not only manufacturing processes. Third and finally, making more effective outsourcing decisions. It is shown that any positive effects of outsourcing manufacturing are more likely to be realized if concurrent initiatives are taken to develop the capability of the manufacturing function. The analysis also indicates a potential for taking a more strategic approach to outsourcing, i.e., outsourcing in order to increase focus on core manufacturing activities and take advantage of the supplier’s higher innovation capability. Moreover, a potential for selecting suppliers more appropriately is also indicated, such as by trying to achieve greater economies of scale. The chosen methodological approach has been to combine two large-scale surveys of representative samples of Swedish engineering industry companies with two multiple case studies. The surveys measured continuous improvement behaviours, lean manufacturing and outsourcing, and provides descriptive statistics as well as tests of theoretical assumptions. The case studies provide a deeper understanding of researched issues. One was designed to illustrate how the Balanced Scorecard may enhance the continuous improvement capability level, and the other, to hearing some voices of the empirical field. / QC 20100525

We propose a mathematical framework that integrates low-level sensory signals from monitoring engineering systems and their components with high-level decision models for maintenance optimization. Our objective is to derive optimal adaptive maintenance strategies that capitalize on condition monitoring information to update maintenance actions based upon the current state of health of the system. We refer to this sensor-based decision methodology as "sense-and-respond logistics". As a first step, we develop and extend degradation models to compute and periodically update the remaining life distribution of fielded components using in situ degradation signals. Next, we integrate these sensory updated remaining life distributions with maintenance decision models to; (1) determine, in real-time, the optimal time to replace a component such that the lost opportunity costs due to early replacements are minimized and system utilization is increased, and (2) sequentially determine the optimal time to order a spare part such that inventory holding costs are minimized while preventing stock outs. Lastly, we integrate the proposed degradation model with Markov process models to derive structured replacement and spare parts ordering policies. In particular, we show that the optimal maintenance policy for our problem setting is a monotonically non-decreasing control limit type policy. We validate our methodology using real-world data from monitoring a piece of rotating machinery using vibration accelerometers. We also demonstrate that the proposed sense-and-respond decision methodology results in better decisions and reduced costs compared to other traditional approaches.

Made available in DSpace on 2014-08-20T13:44:33Z (GMT). No. of bitstreams: 1 dissertacao_denilson_rodrigues.pdf: 642149 bytes, checksum: f1e1c01cac6a74d0ec8a8121ba72296f (MD5) Previous issue date: 2013-04-18 / This work aimed to evaluate the components of soybean yield from different levels of vigor determined by the method of accelerated aging in an official laboratory of seed analysis, in two sowing seasons, the first one being after the first rains, so that the field passed through a period of hydric stress, and the second after the rains have stabilized and there was hydric sufficiency. An experiment was conducted where two batches of high vigor were used, one with a 96% of viability and 92% of vigor and the other with 96% of viability and 91% of vigor. It was also used two batches of middle vigor, one of 91% of viability and 70% of vigor, and the other of 92% of viability and 71% of vigor. We evaluated the following variables: plants per linear meter, plant height, number of seeds per pod, seed number per plant, thousand seed weight and the yield. It was concluded that plants from high vigor seeds showed better performance in all variable component of the yield, except in the thousand seed weight, which was worse, and the use of soybean seeds of middle vigor cause further reduction in yield occurs when more environmental stress. / O trabalho teve como objetivo avaliar características agronômicas e o rendimento de populações de soja oriundas de sementes de diferentes níveis de vigor determinado pelo método de envelhecimento acelerado, em duas épocas de semeadura. A primeira época logo após as primeiras chuvas, para que o campo passasse por um período de estresse hídrico e a segunda época após as chuvas terem se estabilizado e que tivesse suficiência hídrica. Foram utilizados dois lotes de sementes de alto vigor, um de 96% de viabilidade e 92% de vigor e o outro de 96% de viabilidade e 91% de vigor. Também foram utilizados dois lotes de médio vigor, um de 91% de viabilidade e 70% de vigor e o outro de 92% de viabilidade e 71% de vigor. Foram avaliadas as variáveis: número de plantas por metro linear, altura de plantas, número de sementes por vagem, número de sementes por planta, peso de mil sementes e rendimento de sementes. Concluiu-se que plantas provenientes de sementes de alto vigor demonstraram melhor desempenho em todas variáveis avaliadas, exceto no peso de mil sementes. Sob condições de intenso estresse ambiental, o uso de sementes de médio vigor causa maior prejuízo no número de sementes por vagem, número de sementes por planta e na produtividade por área, do que sob condições de estresse reduzido.

As a consequence of the recent deregulation in the electrical power production industry, there has been a shift in the traditional ownership of power plants and the way they are operated. To hedge their business risks, the many new private entrepreneurs enter into long-term service agreement (LTSA) with third parties for their operation and maintenance activities. As the major LTSA providers, original equipment manufacturers have invested huge amounts of money to develop preventive maintenance strategies to minimize the occurrence of costly unplanned outages resulting from failures of the equipments covered under LTSA contracts. As a matter of fact, a recent study by the Electric Power Research Institute estimates the cost benefit of preventing a failure of a General Electric 7FA or 9FA technology compressor at $10 to $20 million. Therefore, in this dissertation, a two-phase data analytics approach is proposed to use the existing monitoring gas path and vibration sensors data to first develop a proactive strategy that systematically detects and validates catastrophic failure precursors so as to avoid the failure; and secondly to estimate the residual time to failure of the unhealthy items. For the first part of this work, the time-frequency technique of the wavelet packet transforms is used to de-noise the noisy sensor data. Next, the time-series signal of each sensor is decomposed to perform a multi-resolution analysis to extract its features. After that, the probabilistic principal component analysis is applied as a data fusion technique to reduce the number of the potentially correlated multi-sensors measurement into a few uncorrelated principal components. The last step of the failure precursor detection methodology, the anomaly detection decision, is in itself a multi-stage process. The obtained principal components from the data fusion step are first combined into a one-dimensional reconstructed signal representing the overall health assessment of the monitored systems. Then, two damage indicators of the reconstructed signal are defined and monitored for defect using a statistical process control approach. Finally, the Bayesian evaluation method for hypothesis testing is applied to a computed threshold to test for deviations from the healthy band. To model the residual time to failure, the anomaly severity index and the anomaly duration index are defined as defects characteristics. Two modeling techniques are investigated for the prognostication of the survival time after an anomaly is detected: the deterministic regression approach, and parametric approximation of the non-parametric Kaplan-Meier plot estimator. It is established that the deterministic regression provides poor prediction estimation. The non parametric survival data analysis technique of the Kaplan-Meier estimator provides the empirical survivor function of the data set comprised of both non-censored and right censored data. Though powerful because no a-priori predefined lifetime distribution is made, the Kaplan-Meier result lacks the flexibility to be transplanted to other units of a given fleet. The parametric analysis of survival data is performed with two popular failure analysis distributions: the exponential distribution and the Weibull distribution. The conclusion from the parametric analysis of the Kaplan-Meier plot is that the larger the data set, the more accurate is the prognostication ability of the residual time to failure model.

Power conservation has become a high priority to South African industries due to recent environmental assessments and electricity price hikes. This research aims to demonstrate to Industry the many simple and cost effective ways to increase their industrial efficiency with simple modifications, as well as making them more aware of common assembly errors that significantly increase power consumption. This has been accomplished with the design, construction and testing of a test rig capable of producing the desired test results which simulate Industry usage. A test rig was required to test certain energy efficient equipment. This dissertation contains an explanation of the tests required, as well as how they were conducted. These test requirements directed the design outcomes of the test rig. Due to the variety of equipment to be tested, and the accuracy required, the test rig had to be fully adjustable. The design process is explained in this dissertation, along with relevant theory with regard to the testing procedures. The testing procedures were designed to be as accurate as possible. The setup equipment and procedure is briefly explained to ensure an understanding of the capabilities of the test rig. This dissertation contains the results obtained from testing a variety of couplings, belts and motors under different conditions. The results obtained show the difference between the efficiency of a standard motor and that of a high efficiency motor. The efficiency comparison of the Poly V TM, Poly Chain® and SPB V-belts showed very distinct advantages and disadvantages of each belt. The coupling testing was conducted under conditions of misalignment, and resulted in distinct differences in the efficiencies of each coupling at different degrees of misalignments. The couplings tested were the Fenaflex®, the Quick-Flex®, and the Fenagrid® coupling. All results obtained were analyzed and discussed in the relevant sections. The results obtained showed that the high efficiency motor is significantly more efficient than the standard motor at full load, although at low loading, the motor efficiencies were very similar. The coupling tests showed the negative effects misalignment has on the efficiency of the Quick-Flex® and Fenagrid® coupling as well as the capability of the Fenaflex® coupling to withstand the effects of large misalignments without significant efficiency loss. v The belt testing revealed the advantages and disadvantages of each type of belt used. This showed that although the synchronous belt did not lose efficiency with decreased tension, it became unstable, and was difficult to keep on the pulley if not aligned correctly. The V-belts can handle low tension well. Prolonged use of the belts can cause them to stretch, lowering the tension into a “danger zone” that will cause the belts to slip. This slip can damage the belt and pulley. At the lower tension of the V-belt, although the efficiency increases slightly, the vibration of the slack side of the belt is significant, and can be dangerous as the belt could jump off the pulley. The Poly V TM belt has some of the advantages of the V-belt, except that it is unable to maintain its friction at low tension, as the belt width prevents it from being wedged into the grooves like the V-belt. The fluid coupling tests showed that the shock loading on a high inertia system can be significantly reduced with the aid of a fluid coupling. The reduced shock loading can reduce energy consumption, and increase the life of electric motors and the equipment that they drive by preventing excessive overloading. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.