Identification of Some Additional Loss Components in High-Power Low-Voltage Permanent Magnet Generators

Permanent magnet generators (PMG) represent the cutting edge technology in modern wind mills. The efficiency remains high (over 90%) at partial loads. To improve the machine efficiency even further, every aspect of machine losses has to be analyzed. Additional losses are often given as a certain percentage without providing any detailed information about the actual calculation process; meanwhile, there are many design-dependent losses that have an effect on the total amount of additional losses and that have to be taken into consideration. Additional losses are most often eddy current losses in different parts of the machine. These losses are usually difficult to calculate in the design process. In this doctoral thesis, some additional losses are identified and modeled. Further, suggestions on how to minimize the losses are given. Iron losses can differ significantly between the measured no-load values and the loss values under load. In addition, with embedded magnet rotors, the quadrature-axis armature reaction adds losses to the stator iron by manipulating the harmonic content of the flux. It was, therefore, re-evaluated that in salient pole machines, to minimize the losses and the loss difference between the no-load and load operation, the flux density has to be kept below 1.5 T in the stator yoke, which is the traditional guideline for machine designers. Eddy current losses may occur in the end-winding area and in the support structure of the machine, that is, in the finger plate and the clamping ring. With construction steel, these losses account for 0.08% of the input power of the machine. These losses can be reduced almost to zero by using nonmagnetic stainless steel. In addition, the machine housing may be subjected to eddy current losses if the flux density exceeds 1.5 T in the stator yoke. Winding losses can rise rapidly when high frequencies and 10–15 mm high conductors are used. In general, minimizing the winding losses is simple. For example, it can be done by dividing the conductor into transposed subconductors. However, this comes with the expense of an increase in the DC resistance. In the doctoral thesis, a new method is presented to minimize the winding losses by applying a litz wire with noninsulated strands. The construction is the same as in a normal litz wire but the insulation between the subconductors has been left out. The idea is that the connection is kept weak to prevent harmful eddy currents from flowing. Moreover, the analytical solution for calculating the AC resistance factor of the litz-wire is supplemented by including an end-winding resistance in the analytical solution. A simple measurement device is developed to measure the AC resistance in the windings. In the case of a litz-wire with originally noninsulated strands, vacuum pressure impregnation (VPI) is used to insulate the subconductors. In one of the two cases studied, the VPI affected the AC resistance factor, but in the other case, it did not have any effect. However, more research is needed to determine the effect of the VPI on litz-wire with noninsulated strands. An empirical model is developed to calculate the AC resistance factor of a single-layer formwound winding. The model includes the end-winding length and the number of strands and turns. The end winding includes the circulating current (eddy currents that are traveling through the whole winding between parallel strands) and the main current. The end-winding length also affects the total AC resistance factor.

Excelling in procurement : IT Contract Management with Lean and Six Sigma. Case study on legacy contract management at Philips Global IT.

Few people see both opportunities and threats coming from IT legacy in current world. On one hand, effective legacy management can bring substantial hard savings and smooth transition to the desired future state. On the other hand, its mismanagement contributes to serious operational business risks, as old systems are not as reliable as it is required by the business users. This thesis offers one perspective of dealing with IT legacy – through effective contract management, as a component towards achieving Procurement Excellence in IT, thus bridging IT delivery departments, IT procurement, business units, and suppliers. It developed a model for assessing the impact of improvements on contract management process and set of tools and advices with regards to analysis and improvement actions. The thesis conducted case study to present and justify the implementation of Lean Six Sigma in IT legacy contract management environment. Lean Six Sigma proved to be successful and this thesis presents and discusses all the steps necessary, and pitfalls to avoid, to achieve breakthrough improvement in IT contract management process performance. For the IT legacy contract management process two improvements require special attention and can be easily copied to any organization. First is the issue of diluted contract ownership that stops all the improvements, as people do not know who is responsible for performing those actions. Second is the contract management performance evaluation tool, which can be used for monitoring, identifying outlying contracts and opportunities for improvements in the process. The study resulted in a valuable insight on the benefits of applying Lean Six Sigma to improve IT legacy contract management, as well as on how Lean Six Sigma can be applied in IT environment. Managerial implications are discussed. It is concluded that the use of data-driven Lean Six Sigma methodology for improving the existing IT contract management processes is a significant addition to the existing best practices in contract management.

The pH-dependent phase distribution of wood pitch components in papermaking processes

Wood contains only a very small amount of lipophilic extractives, commonly known as wood pitch. The pitch is known to cause severe problems in papermaking processes. The amount of pitch in process waters can be decreased by seasoning of the raw material prior to pulping, pulp washing, removal of pitch by flotation, adsorption of pitch onto various mineral surfaces, and retention of pitch to the fibre material by cationic polymers. The aim of this study was to determine the influence of pH on some of the methods used for pitch control. Experiments were performed using laboratory-made wood pitch emulsions with varying pH, salt concentration, hemicellulose concentration and pitch composition. These emulsions were used to study the phase distribution of resin and fatty acids, the colloidal stability of pitch with and without steric stabilisation by galactoglucomannans, and the interactions between wood pitch and mineral particles. Purification of unbleached and peroxidebleached mill process water was performed by froth flotation in combination with a foaming agent. The distribution of resin and fatty acids (RFAs) between colloidal pitch droplets and the water phase was very dependent on pH. At pH 3, almost all of the RFAs were attached to the pitch droplets, while increasing the pH led to increasing concentration of dissolved RFAs in the water phase. The presence of salt shifted the release of RFAs towards higher pH, while lower ratio of neutral pitch in the emulsion resulted in release of RFAs at lower pH. It was also seen that the dissolution and adsorption of RFAs at sudden pHchanges takes place very quickly. Colloidal pitch was more stable against electrolyte-induced aggregation at higher pH, due to its higher anionic charge. The concentration of cationic polymers needed to aggregate colloidal pitch also increased with increasing pH. The surface characteristics of solid particles, such as amount of charged groups, were very important for understanding their interactions with colloidal wood pitch. Water-soluble galactoglucomannans stabilised the colloidal pitch sterically against aggregation, but could not completely prevent interactions between wood pitch and hydrophilic particles. Froth flotation of unbleached and peroxidebleached process water showed that the pitch could be removed more effectively and selectively at low pH, compared to at neutral pH. The pitch was removed more effectively, using lower concentrations of foaming agent, from peroxide-bleached water than from unbleached water. The results show that pH has a major impact on various pulping and papermaking processes. It determines the anionic charge of the colloidal pitch and the solubility of certain pitch components. Because of this, the pH influences the effectiveness of pitch retention and removal of pitch. The results indicate that pitch problems could be diminished by acknowledging the importance of pH in various papermaking processes.

Thermal reactions of the major hydrocarbon components of biomass gasification gas

Gasification of biomass is an efficient method process to produce liquid fuels, heat and electricity. It is interesting especially for the Nordic countries, where raw material for the processes is readily available. The thermal reactions of light hydrocarbons are a major challenge for industrial applications. At elevated temperatures, light hydrocarbons react spontaneously to form higher molecular weight compounds. In this thesis, this phenomenon was studied by literature survey, experimental work and modeling effort. The literature survey revealed that the change in tar composition is likely caused by the kinetic entropy. The role of the surface material is deemed to be an important factor in the reactivity of the system. The experimental results were in accordance with previous publications on the subject. The novelty of the experimental work lies in the used time interval for measurements combined with an industrially relevant temperature interval. The aspects which are covered in the modeling include screening of possible numerical approaches, testing of optimization methods and kinetic modelling. No significant numerical issues were observed, so the used calculation routines are adequate for the task. Evolutionary algorithms gave a better performance combined with better fit than the conventional iterative methods such as Simplex and Levenberg-Marquardt methods. Three models were fitted on experimental data. The LLNL model was used as a reference model to which two other models were compared. A compact model which included all the observed species was developed. The parameter estimation performed on that model gave slightly impaired fit to experimental data than LLNL model, but the difference was barely significant. The third tested model concentrated on the decomposition of hydrocarbons and included a theoretical description of the formation of carbon layer on the reactor walls. The fit to experimental data was extremely good. Based on the simulation results and literature findings, it is likely that the surface coverage of carbonaceous deposits is a major factor in thermal reactions.

Corporate social responsibility in procurement: environmentally responsible practices case study

The main object of this study is to find and define environmentally responsible procurement practices and characterize responsible procurement.

Exploring business models for medical games: Key components and challenges

The costs of health care are going up in many countries. In order to provide affordable and effective health care solutions, new technologies and approaches are constantly being developed. In this research, video games are presented as a possible solution to the problem. Video games are fun, and nowadays most people like to spend time on them. In addition, recent studies have pointed out that video games can have notable health benefits. Health games have already been developed, used in practice, and researched. However, the bulk of health game studies have been concerned with the design or the effectiveness of the games; no actual business studies have been conducted on the subject, even though health games often lack commercial success despite their health benefits. This thesis seeks to fill this gap. The specific aim of this thesis is to develop a conceptual business model framework and empirically use it in explorative medical game business model research. In the first stage of this research, a literature review was conducted and the existing literature analyzed and synthesized into a conceptual business model framework consisting of six dimensions. The motivation behind the synthesis is the ongoing ambiguity around the business model concept. In the second stage, 22 semi-structured interviews were conducted with different professionals within the value network for medical games. The business model framework was present in all stages of the empirical research: First, in the data collection stage, the framework acted as a guiding instrument, focusing the interview process. Then, the interviews were coded and analyzed using the framework as a structure. The results were then reported following the structure of the framework. In the results, the interviewees highlighted several important considerations and issues for medical games concerning the six dimensions of the business model framework. Based on the key findings of this research, several key components of business models for medical games were identified and illustrated in a single figure. Furthermore, five notable challenges for business models for medical games were presented, and possible solutions for the challenges were postulated. Theoretically, these findings provide pioneering information on the untouched subject of business models for medical games. Moreover, the conceptual business model framework and its use in the novel context of medical games provide a contribution to the business model literature. Regarding practice, this thesis further accentuates that medical games can offer notable benefits to several stakeholder groups and offers advice to companies seeking to commercialize these games.

Development of Project Logistics in Engineering, Procurement and Construction Projects

The aim of this Master’s Thesis is to develop project logistics functions in large scale en-gineering, procurement and construction projects. The background of the research topic is compounded from two separate subjects; OPAL Program and case study of an actual EPC project. The purpose is to examine Project Logistics process in accordance with OPAL Program as well as logistics process in focus EPC project. Both entities are researched by using the case study research methodology. Logistics process of the focus EPC project is described as well as presented and in addi-tion, logistics related findings and observations are introduced. Significant findings and observations are found from logistics costs as well as shipment volume estimations in the early phase of the focus ECP project. A notable finding is also that because goods were transported as readily assembled as possible it caused expensive oversized cargo deliveries. From findings and observation of the focus EPC project it can be derived that logistics has to be involved in the early sales phase in order to receive more accurate logistics cost esti-mations for project deliveries. It is also noticed that in order to obtain savings in logistics costs, oversized deliveries must be avoided.

Foreign exchange exposure management in a fuel procurement company operating in the commodity markets

Fluctuating commodity prices, foreign exchange rates and interest rates are causing changes in cash flows, market value and the companies’ profit. Most of the commodities are quoted in US dollar. Companies with non-dollar accounting face a double risk in the form of the commodity price risk and foreign exchange risk. The objective of this Master’s thesis is to find out how companies under commodity should manage foreign exchange exposure. The theoretical literature is based on foreign exchange risk, commodity risk and foreign exchange exposure management. The empirical research is done by using constructive modelling of a case company in the oil industry. The exposure is model with foreign exchange net cash flow and net working capital. First, the factors affecting foreign exchange exposure in case company are analyzed, then a model of foreign exchange exposure is created. Finally, the models are compared and the most suitable method is defined. According to the literature, foreign exchange exposure is the foreign exchange net cash flow. However, the results of the study show that foreign exchange risk can be managed also with net working capital. When the purchases, sales and storage are under foreign exchange risk, the best way to manage foreign exchange exposure is with combined net cash flow and net working capital method. The foreign exchange risk policy of the company defines the appropriate way to manage foreign exchange risk.

Characterization and Investigation on Material Compatibilities of Building Integrated Photovoltaic Module Components

Building Integrated Photovoltaics (BIPV) are considered as the future of photovoltaic (PV) technology. The advantage of BIPV system is its multi-functionality; they fulfil the functions of a building envelope with the added benefit of generating power by replacing the traditional roofing and façade materials with PV that generate power. In this thesis, different types of PV cells and modules have been described in detail with their efficiencies and usage trends in the last decade. The different BIPV products for roof and façade are discussed in detail giving several examples. The electricity generation potential of BIPV in selected countries is compared with their actual electricity consumption. Further, the avoided greenhouse gas (GHG) emissions associated with electricity generation from traditional sources and transportation and distribution (T&D) losses are calculated. The results illustrate huge savings in GHGs. In BIPV different types of façade and backsheets are used. In this thesis, selected backsheets and façade were characterized in terms of their surface structure identification using infrared spectroscopy (FTIR-ATR), scanning electron microscopy with energy dispersive X-ray (SEM-EDX) and physical characterization using surface energy measurements. By using FTIR-ATR, surface polymeric materials were identified and with SEM-EDX, identification of the surface elements was possible. Surface energy measurements were useful in finding the adhesives and knowing the surface energies of the various backsheets and façade. The strength of adhesion between the facade and backsheets was studied using peel test. Four different types of adhesives were used to study the fracture pattern and peel tests values to identify the most suitable adhesive. It was found out that pretreatment increased the adhesive strength significantly.