Wind power is one of the fastest growing production methods of electric energy. The expansion of wind power in Sweden are focused to northern counties. There are advantages as good wind conditions and large unexploited areas to build wind farms in the north, but there are also problems caused by the long winters. Due to the long periods of cold climate, ice and snow accumulation on blades are a safety risk, induces production losses and causes wear at wind turbine components. The commercial de-icing systems are not fulfilling the demands of being cost effective and are mainly focusing the heating to the leading edge. Therefore a new de-icing system based on infrared radiation has been investigated. This system is supposed to be placed at the wind turbine tower and de-ice one blade at a time. Experiments with this new de-icing system has been performed in small and full scale at a section of a real wind turbine blade. The experiments were carried out in facilities of Arctic Falls in Piteå. Different parameters as power demand of the heaters, distance between blade and heaters, wavelength of the radiation, influence by the surrounding temperature and total de-icing time were evaluated. Results showed that the largest impact of the efficiency and de-icing time were induced by the distance and width of the radiation spectrum for the heaters. Three types of filaments with different peaks of wavelengths were investigated and the most efficient de-icing was achieved when using a combination of heaters. Measurements of intensity together with de-icing experiments showed that the optimal distance from the blade was 1.5 m for heaters with standard reflectors. The main conclusion from the experiments with an infrared de-icing system is that it works. But not efficient enough to compete with the commercial systems of today even though it manage to de-ice the whole blade instead of just the leading edge. But this de-icing system has good potential if the heaters first of all are developed to radiate a more concentrated beam of radiation that is only focusing at the blades. The new method is estimated to be an lower investment due to that the techniques of infrared heaters are already well implemented in other areas. But more economic calculations has to be done to further motivate the work.

This project explores the idea of implementing an electronic device that can melt away ice from frozen bike locks. It narrates the process of starting with no knowledge of how heating works and ending with a manufactured and soldered PCB with limited heating capability. Resistance heating and induction heating was studied in the initial phase of the project. Which proceeded into designing the complete schematic of the induction heater. A prototype was built which advanced further to the development of tools and ways to measure inductance, resonant frequency and temperature before the tests of the performance. When the performance tests were done the induction heater was optimized and later designed in eagle. A PCB circuit was ordered which later was soldered until completion.  The result was an induction heater in PCB form with limited functionality compared to the data of the prototype, due to faulty layout of the circuit. The performance of the end result was 20.02 degrees C to 33.20 degrees C in 11 minutes. The data from the prototype suggests that the induction heater can melt the ice from frozen bike locks since the performance was 21.96 degrees C to 62.02 degrees C in 4 minutes. Any rise in temperature over the boiling point of water 0 degrees C is good but tests in real winter conditions needs to be done to definitively confirm success. The mayor problem is whether a battery can provide with the required energy without getting to big or expensive. If the answer is yes then the induction heater of this project can be used regularly but the manufacturing costs would still be high.

<p><strong>Problem: </strong>A Polish company produces heaters wants to enter the Swedish market. The decision maker needs information about the Swedish market both the general information about Sweden and specific information about the Swedish heater market. And some specific questions are asked by the firm in order to get a deeper view of the present heater market in Sweden.</p><p> </p><p><strong>Purpose</strong>: If Swedish market ‘right’ (a farsighted choice)? Suppose the answer is ‘yes’, then how to enter and operate on the Swedish market within the environmental context of Sweden and the present Swedish heater market? Then suppose the answer is ‘no’, should the Polish firm leave or fix the problems?</p><p> </p><p>To achieve the goal, information of environmental context (ecological, sociocultural, technological, economic, political/legal and competitive) about Sweden should be collected. And according to the firm’s specific questions, answers should be collected by means of exploratory research. Suggestions about entering steps and future operation are to be fulfilled.  </p><p> </p><p><strong>Method</strong>: Qualitative Research</p><p> </p><p><strong>Results</strong>: In all, this thesis provides information to evaluate the chances and challenges, and proves Sweden is a ‘right’ choice -- the firm can win market share (reasons will be stated in following chapters) despite of the competition from present competitors.  Further applications of entering and operating on the Swedish heater market are available.</p><p> </p><p>General information about Sweden combined with detailed information of the present heater market were collected, analyzed and discussed. The presentation of the information helps evaluate the attractiveness of the Swedish market. Further study applies procedures of entering Sweden and operation after entering, which will be of vital importance for competing on the Swedish heater market when the decision maker determines to choose Sweden.</p>

Microfabricated thermal cyclers for nucleic acid amplification by using polymerase chain reaction (PCR) have been demonstrated by several groups over the last decade, with improved cycling speed and smaller volumes when compared to conventional bench-top cyclers. However, high fabrication costs coupled with difficulties in temperature sensing and control remain impediments to commercialization. In this study we have used a silicon-glass device that takes advantage of the high thermal conductivity of silicon but at the same time utilizes minimum number of fabrication steps to make it suitable for disposable applications. The thermal cycler is based on noncontact induction heating developed in this group. The microchip reaction kinetics is studied for the first time in-situ during PCR, using a real-time fluorescence block that is capable of data acquisition every 0.7 s from the microchip. The fluorescence information from SYBR green I dye is used to optimize microchip amplification reactions and confirm the product by melting curve analysis. We have also developed a novel non-contact temperature sensing technique using SYBR green fluorescence that can be used for miniaturized PCR devices. The thesis is organized into the following chapters. In chapter 1 we introduce the basic biology ideas that are required to understand DNA amplification. DNA based analysis requires amplification of low initial concentrations to above detectable limits using a technique known as polymerase chain reaction (PCR). In this process, the sample is cycled through three thermal steps for 3040 times to produce multiple copies of DNA. In microchip PCR, conventional polypropylene tubes using 2050 µL volume are replaced by miniaturized devices using ~1 µL sample volumes. The device response improves in terms of ramp rate and total analysis time due to the small volume and smart design of the materials. In this chapter we summarize some of the issues important for miniaturized PCR devices and compare them with commercial tube PCR systems. In chapter 2 we describe the induction heating technique that was developed by our group for miniaturized devices. Induction heating is a noncontact heating technique unlike resistive heating which has been commonly used for microchip PCR. Though resistive heating is very efficient in terms of heat transfer efficiency, it is not suitable for disposable devices and requires multi-step microfabrication. Other non-contact heating techniques such as hot air and IR heating require larger size arrangements that are not suitable for miniaturized devices. The heating was verified by using a thermocouple soldered at the back of the secondary plate that was also used for feedback to the comparator circuit for control. The simple on-off circuit was able to control within ±0.1 ◦C with heating and cooling ramp rates of 25 ◦C/s and 2.5 ◦C/s respectively. In this chapter, we also describe the design and fabrication of the silicon-glass microchip fabricated in our lab. We have used silicon-glass hybrid device for PCR in which glass with a 2 mm drilled hole is anodically bonded to an oxidized silicon surface. The hole formed the static reservoir for 3 µL volume of amplification solution. During PCR, the solution needs to be cycled to high temperature of ~95 ◦C. Hence it was necessary to seal the tiny droplet of liquid against evaporation at this temperature. The devices after being filled by sample were covered by 4 µL of mineral oil to serve as an evaporation barrier. It was easy to recover the whole sample after amplification for further testing. Chapter 3 describes the development of a fluorescent block for SYBR green I dye (SG) used for real-time monitoring of the amplification. The block contains a blue LED for excitation, a dichroic beamsplitter, and silicon photodiode along with filters and focusing optics. Signal levels being weak, we incorporated lock-in detection technique. A TTL at 190 Hz was used to pulse the excitation source and detect the emission at the same frequency using a commercial lock-in amplifier. The block was first characterized using a commercial thermal cycler and polypropylene tubes with different dilution of initial template copy number, and the results crosschecked with agarose gel electrophoresis. Performing continuous monitoring every 0.7s within cycles, we discovered interesting features during extension which have not been studied previously. During the constant temperature extension step, the fluorescence shows a rise and then saturates until the temperature is cycled to the next set point. We have confirmed the same behavior in single cycle extension control experiments and established its connection with polymerase extension activity. We were thus able to extract the activity rate for two different kinds of polymerase in-situ during PCR. By monitoring PCR reactions with different fixed extension times, we were able to determine the optimum conditions for tube PCR. Chapter 4 implements the ideas of fluorescence monitoring from tube that was explained in the previous chapter for the silicon-glass microchip. Since the microchip uses parameters such as sample volume, ramp rates, stay time etc. which are different from tube PCR, we performed several initial test experiments to establish key capabilities such as low volume detection, 3 µL amplification, surface passivation of silicon-glass etc. The same fluorescence block was used to obtain DNA melting point information by continuously monitoring ds-DNA with SG while the temperature is ramped slowly (melting curve analysis). Depending on ds-DNA present, the fluorescence gives a melting temperature (TM ), which was used to calibrate the mix temperature with respect to the thermocouple sensor. After successfully calibrating the microchip, we confirmed complete chip PCR in silicon-glass devices using induction heater. The continuous monitoring of chip PCR gave similar curves as obtained previously for tubes except that the signal level was lower in silicon devices. Extension fluorescence information was used to find an optimum temperature for microchip that shows a maximum activity rate. Similarly the reaction time was optimized in-situ during PCR by using continuous fluorescence data in a feedback experiment. The commercial lock-in amplifier was also replaced by a homemade circuit to successfully pickup fluorescence signal from the microchip during melting curve analysis. In chapter 5, we describe a novel technique to sense the temperature from the microchip without touching the sample volume. Usually the temperature is monitored by a sensor spatially separated from the mix and it has always been challenging to measure the exact temperature accurately. Most of the sensors are not biocompatible and too large in size to be placed inside the small volume of liquid. We have developed a protocol that involves SG fluorescence with addition of excess sensor DNA to the amplification solution. The sensor DNA added into the mix is non specific to the primer used for amplification of the template. It therefore does not participate in the amplification and its number remains unchanged throughout the 3040 cycles of PCR. If the amount of sensor DNA is titrated accurately, it will saturate the fluorescence envelope which then shows very reproducible thermal response with cycling. We have used this thermal response of the fluorescence for feedback as a temperature sensor. The fluorescence feedback was shown to produce identical amount of product in comparison to thermocouple feedback. The product can also be verified by melting curve analysis if the sensor DNA is chosen carefully depending on the product. In this chapter we also discuss some preliminary experiments with smart devices that will use dye based temperature sensor and control along with fluorescence based amplification monitoring. Chapter 6 summarizes the thesis and discusses some of the future areas which can be explored in the field of microchip PCR devices.

Problem: A Polish company produces heaters wants to enter the Swedish market. The decision maker needs information about the Swedish market both the general information about Sweden and specific information about the Swedish heater market. And some specific questions are asked by the firm in order to get a deeper view of the present heater market in Sweden.   Purpose: If Swedish market ‘right’ (a farsighted choice)? Suppose the answer is ‘yes’, then how to enter and operate on the Swedish market within the environmental context of Sweden and the present Swedish heater market? Then suppose the answer is ‘no’, should the Polish firm leave or fix the problems?   To achieve the goal, information of environmental context (ecological, sociocultural, technological, economic, political/legal and competitive) about Sweden should be collected. And according to the firm’s specific questions, answers should be collected by means of exploratory research. Suggestions about entering steps and future operation are to be fulfilled.     Method: Qualitative Research   Results: In all, this thesis provides information to evaluate the chances and challenges, and proves Sweden is a ‘right’ choice -- the firm can win market share (reasons will be stated in following chapters) despite of the competition from present competitors.  Further applications of entering and operating on the Swedish heater market are available.   General information about Sweden combined with detailed information of the present heater market were collected, analyzed and discussed. The presentation of the information helps evaluate the attractiveness of the Swedish market. Further study applies procedures of entering Sweden and operation after entering, which will be of vital importance for competing on the Swedish heater market when the decision maker determines to choose Sweden.

This master thesis is about an investigation of anti-moisture methods for a nonhermeticelectronics enclosure containing a number of printed circuit boards(PCB) and placed in a severe climatic environment. The relevant theoretical background was provided first. It included the impact of moisture on electronics, some useful psychrometrics concepts, heat transfer fundamentals, introduction of environmental test, temperature and humiditysensing techniques, computational fluid dynamics (CFD) modelling, antimoisture methods and commercial heaters in the current marketing. Then a CFD modelling methodology was developed and validated based on experiment data. An extra heater was added to the enclosure to prevent water adsorption on printed circuit assemblies (PCA) surfaces. The heat dissipation and switch-on period strategies were parametrically studied in order to maintain the internal relative humidity below 60% in the vicinity of PCA surfaces, according to the relative humidity control method. In the end, results obtained from the environmental tests and the CFD simulations were presented and analyzed. Conclusions and future work were also discussed.

This report includes development of an already designed solar water heater. The product shall be constructed in a way that it will suit a manufacturing line in Kampala, Uganda. To find the most suitable design for each area a research was carried out which included study visits, interviews and background reading. It provided the following results: Regarding the attachment of in- and outgoing pipes from the water tank many methods were taken into consideration and it was found that the best and most suitable way for this case is to weld the fittings using a weld robot. Regarding the fitting of the acrylic, a suitable solution is to make a flange when vacuum forming the plastic casing to further support the design. This could also be used to waterproof the case by using a sealing material. A suggestion of using pre-molded PU-foam is also presented. Regarding the ability to open the case for maintenance, two solutions were recommended. Either the use of spire clips or having the clips integrated into the casing. Regarding the calculation of material usage when deep drawing the tank and collector, it is possible to do a reasonably accurate assumption. The complicated design in this product makes the estimation less accurate. It is recommended that test draws are done and often the machine producer has more precise numbers. Regarding the coloring of the collector; chemical coloration is not possible on a galvanized surface. The method used is painting, either with powder coating or with wet paint.

In Cape Town, South Africa, households' acces to modern and clean energy services needs to be increased. However, use of coal-powered electricity stresses the environment and power cuts create an urgent need to reduce the demand. Solar water heaters (SWH) could enable increasing access and affordability of energy services in the townships without stressing the environment or increasing the demand for coal-powered electricity. However, it is an expensive solution and the majority of the city-level efforts still target the high-consuming households. The benefits for the poor households from using a SWH could though outweigh the high capital investements and meet the needs of the city's environmental management. The results from this study of 20 households showed that by having an affordable, clean and reliable source of energy for heating water, households were able to use more warm water for bathing and reduce their use of electricity and paraffin. This resulted in improvements in health and quality of life. Also, households' general spending on energy was reduced, which for some enabled an increase in income-generating activities. The use of solar-heated showers was found to be restricted by the issue of sharing and it is argued that the benefits would be greater if each households had their own solar water heater. The estimated increase in water use might raise questions of the solution's future feasibility. Despite this, it can be argued that the changes in the households' energy and water use are likely to result in significant improvements in the households' well-being which could also benefit the city as a whole.

In this thesis, experimental and numerical studies have been carried out to investigate the performance of a solar desalination system working on humidification-dehumidification principle under the climatological conditions of Ankara, Turkey. The desalination unit was configured mainly by a double-pass flat plate solar air heater with two glass covers, pad humidifier, storage tank and dehumidifying exchanger. The system used in this work is based on the idea of closed water and open air cycles. A computer simulation program based on the mathematical model was developed by means of MATLAB software to study the effect of different environmental, design, and operational parameters on the desalination system productivity. In this simulation program, the fourth order Runge-Kutta method was used to solve the energy balance equations simultaneously and numerically. In order to compare the obtained theoretical results with experimental ones and validate of the developed mathematical model of the system, an experimental study has been carried out. For that, an experimental set-up was designed, constructed and tested at the solar house of the Mechanical Engineering Department of METU. In addition, the existing solar desalination system was integrated with an evacuated tubular solar water heater unit (closed water circulation) and performance of the system has been studied experimentally.

<p><p>This master thesis is about an investigation of anti-moisture methods for a nonhermeticelectronics enclosure containing a number of printed circuit boards(PCB) and placed in a severe climatic environment.</p><p>The relevant theoretical background was provided first. It included the impact of moisture on electronics, some useful psychrometrics concepts, heat transfer fundamentals, introduction of environmental test, temperature and humiditysensing techniques, computational fluid dynamics (CFD) modelling, antimoisture methods and commercial heaters in the current marketing.</p><p>Then a CFD modelling methodology was developed and validated based on experiment data. An extra heater was added to the enclosure to prevent water adsorption on printed circuit assemblies (PCA) surfaces. The heat dissipation and switch-on period strategies were parametrically studied in order to maintain the internal relative humidity below 60% in the vicinity of PCA surfaces, according to the relative humidity control method.</p><p>In the end, results obtained from the environmental tests and the CFD simulations were presented and analyzed. Conclusions and future work were also discussed.</p></p>