Multi-Body System Simulation combined with System Identification was developed as a method for determining the stability characteristics of a human powered helicopter(HPH) configurations. HPH stability remains a key component for meeting competition requirements, but has not been properly treated. Traditional helicopter dynamic analysis is not suited to the HPH due to its low rotation speeds and light weight. Multi-Body System Simulation is able to generate dynamic response data for any HPH configuration. System identification and linear stability theory are used to determine the stability characteristics from the dynamic response. This thesis focuses on the method development and doesn't present any HPH analysis results.

The Internet of Things (IoT) is an infrastructure of physical objects connected via the Internet that can exchange data to achieve efficient resource management. Billions of devices must be self-powered and low-cost considering the massive scale of the IoT. Thus, there is a need for low-cost ambient energy harvesters to power IoT devices. It is a challenging task since ambient energy might be unpredictable, intermittent and insufficient. For example, solar energy has limitations such as intermittence and unpredictability despite utilizing the highest power availability and relatively mature technology. Designing a multi-source energy harvester (MSEH) based on continuous and ubiquitous ambient energy sources might alleviate these issues by providing versatility and robustness of power supply. However, combining several energy harvesters into one module must be done synergistically to ensure miniaturization, compactness and more collected energy. Also, additive manufacturing techniques must be used to achieve low-cost harvesters and mass manufacturability. This dissertation presents two different kind of ambient energy harvesters, namely radio frequency energy harvester (RFEH) and thermal energy harvester (TEH). Each harvester is individually optimized and then synergistically combined into a MSEH. First, RFEH is designed for triple-band harvesting (GSM900, GSM1800, 3G2100) using the antenna-on-package concept and fabricated through 3D and screen printing. TEH collects energy from temperature fluctuations of ambient environment through a combination of thermoelectric generators and phase change materials. It is adapted specifically for the desert conditions of Saudi Arabia. Later, TEH and RFEH are combined to realize MSEH. Smart integration is achieved by designing a dual-function component, heatsink antenna, that serves as a receiving antenna of RFEH and a heatsink of TEH. The heatsink antenna has been optimized for both antenna radiation performance and heat transfer performance. Field tests showed that the MSEH can collect 3680μWh energy per day and the outputs of TEH and RFEH have increased 4 and 3 times compared to the independent TEH and RFEH respectively. To validate the utility of the MSEH, a temperature/humidity sensor has been successfully powered by the MSEH. Overall, sensor’s data can be wirelessly transmitted with time intervals of 3.5s, highlighting the effectiveness of the synergistic MSEH.

Hip-knee-ankle-foot (HKAF) prostheses are full lower limb devices for people with hip amputations. They are designed to enable individuals to regain their mobility and move freely with little restriction. HKAFs typically have high rejection rates among users, as well as gait asymmetry and increased trunk anterior-posterior lean and pelvic tilt. In this thesis, a novel integrated hip-knee (IHK) unit was designed and evaluated to address the limitations of existing solutions. This IHK combines powered hip and microprocessor controlled knee joints into one structure, with shared electronics, sensors, and batteries. The unit is also adjustable to the user leg length by a prosthetist. ISO-10328 standard mechanical testing demonstrated acceptable structural safety and rigidity. Successful functional testing involved three able-bodied participants walking with the IHK in a hip prosthesis simulator. Hip and knee joint angles and pelvic tilt angles were recorded, gait characteristics were analyzed using video recordings. Testing showed that the participants were able to walk using the IHK, and data showed that participants used different walking strategies. Points of improvement were identified for future development of the thigh unit, including completion of a synergistic gait control system, improved battery holding mechanism, and amputee user testing.

Detta examensarbete riktar sig in på att undersöka olika typer av solceller, batterier och lampor för att ta fram och jämföra två system av solcellsdriven gatubelysning i Stockholm och Kiruna. Sverige befinner sig väldigt norr ut på jordklotet vilket innebär en stor kontrast i soltimmar under sommar- och vinterhalvåret. Arbetets huvudsyfte är att ta fram ett solcellsdrivet system där energi genererad under sommaren kan lagras i ett batteri och sedan kompensera för energiunderskottet under vintern. Resultaten visar att skillnaden av genererad energi är stor beroende på vilken solcell som används. Beroende på val av solceller skiljer sig även kravet på batterikapaciteten för respektive ort. Energiupptaget från solceller i Stockholm och Kiruna skiljer sig markant, detta beror på olikheten av globalstrålningen.  Resultaten från kostnadsberäkningen visar att belysningssystemen som studeras i arbetet är dyrare i Kiruna än i Stockholm, detta beror på skillnaden i krav på batterikapacitet utifrån genererad energi från solcellerna. Val av batteri- och solcellstyp har även en påverkan på kostnaden. / This thesis focuses on examining different types of solar cells, batteries, and lamps to develop and compare two systems of solar-powered street lighting in Stockholm and Kiruna. Sweden is located very north of the globe, which means a great contrast in sunny hours during the summer and winter months. The main purpose of the study is to develop a solar-powered system where energy generated during the summer can be stored in a battery and then compensate for the energy deficit during the winter. The results show that the difference in generated energy is large depending on which solar cell is used. Depending on the choice of solar cells, the requirement for battery capacity for each location also differs. The energy uptake from solar cells in Stockholm and Kiruna differs significantly, this is due to the difference in global radiation. The results from the cost calculations show that the lighting systems studied in the thesis are more expensive in Kiruna than in Stockholm, this is due to the difference in requirements for battery capacity based on the energy generated from the solar cells. The choice of battery and solar cell type also has an impact on the cost.

This work presents an investigation of a piezoelectric sensor based energy harvesting system, which collects energy from the surrounding environment. Increasing costs and scarcity of fossil fuels is a great concern today for supplying power to electronic devices. Furthermore, generating electricity by ordinary methods is a complicated process. Disposal of chemical batteries and cables is polluting the nature every day. Due to these reasons, research on energy harvesting from renewable resources has become mandatory in order to achieve improved methods and strategies of generating and storing electricity. Many low power devices being used in everyday life can be powered by harvesting energy from natural energy resources. Power overhead and power energy efficiency is of prime concern in electronic circuits. In this work, an energy harvester is modeled and simulated in Simscape™ for the functional analysis and comparison of achieved outcomes with previous work. Results demonstrate that the harvester produces power in the 0 μW to 100 μW range, which is an adequate amount to provide supply to low power devices. Power efficiency calculations also demonstrate that the implemented harvester is capable of generating and storing power for low power pervasive applications.

The pressing needs for cost effective electric power that provides both high reliability and high quality is creating an opportunity for alternative energy distributed generation (DG). To determine the economic and technical feasibility of such alternative energy distributed generation facilities, electric power customers must understand their electric usage patterns, economic considerations, local alternative fuel supplies and available DG technologies. This thesis discusses the economic and technical feasibility of establishing a distributed generation installation. As a part of technical feasibility, an evaluation has been done to compare DG size and location impact on the operation of the I 13 node test distribution systems. This evaluation was carried out by performing the distribution power flow that provides the information about voltage profile, losses in the system and feeder power factor. This information was used to determine the optimal location of DG in the test distribution system. Additionally, this part focuses on the importance of power utilization assessment in distributed generation planning. It also discussed the load utilization assessment that focus on step-by-step analysis of load profiles of different facilities such as Choctaw Laundromat, Choctaw Geyser Falls (water park) and Golden Moon Casino. The second part of this thesis?s work resulted in an informative and useful economic analysis tool, DG-ECON with which the user can document the study results and analyze them for economic feasibility with minimal effort. The economic feasibility of a biomass-based renewable energy installation is clearly shown by developing a user interface spreadsheet in Microsoft Excel. The spreadsheet calculates project-screening information in the form of a 20-year life cycle cost analysis. This cost analysis that enables users to define projects that are most energy efficient and offer the greatest financial benefit. The emphasis is on the user interface features of the application to make the application as user friendly as possible. The application has both numerical and graphical data representation using some of the features of Microsoft Visual Basic.

No description available.

The triboelectric nanogenerator (TENG) has attracted global attention in the fields of power sources and self-powered sensors. By coupling the omnipresent triboelectrification effect and the electrical induction effect, the TENGs can transduce ambient mechanical energy into electrical energy. Such energy could be consumed instantaneously or stored for later use. In this way, they could be deployed distributedly to be compatible power sources in the era of the internet of things (IoTs), completing the powering structure that is currently relying on power plants. Also, the electrical signals can reflect the environment changes around the TENGs. Thus, the TENGs can serve as self-powered sensors in the IoTs. In this work, we adopted two approaches for TENG fabrication: the thermal drawing method (TDP) and 3D printing. With TDP, we have fabricated scalable fiber-based triboelectric nanogenerators (FTENG), which have been woven into textiles by an industrial loom for wearable use. This fabrication process can supply FTENG on a large scale and fast speed, bridging the gap between the TENG and weaving industry. With 3D printing, we have fabricated TENGs that are compatible with the shape of arbitrary substrates. They have been used as biocompatible sensors: human-skin-compatible TENG has been used to recognize silent speech in real-time by sensing the chin movement; the porcine-kidney-shaped fiber mesh has been used to monitor the perfusion rate of the organ. These works have extended the territory of TENGs and can be critical components in the IoTs. / Ph.D. / Portable electronic devices have become important components in our daily lives, and we are entering the era of the Internet of Things (IoTs), where everyday objects can be interconnected by the internet. While electricity is essential to all of these devices, the traditional power sources are commonly heavy and bulky and need to be recharged or directly connected to the immobile power plants. Researchers have been working to address this mismatch between the device and power systems. The triboelectric nanogenerators (TENG) are good candidates because they can harvest energy in the ambient environment. The users can use them to generate electricity by merely making the rubbing motion. In this work, we report two fabrication methods of the fiber-based triboelectric nanogenerators (FTENG). With the thermal drawing process, we have fabricated sub-kilometer-long FTENG and wove it with the regular cotton yarn into textiles. The wearable power source is human friendly as it does not induce any extra weight load for the user. Besides, we have demonstrated that such long fibers can work as self-powered distributed sensors, such as a Morse code generator. With 3D printing, we have fabricated FTENG-based devices that conform to the working substrates, which can be any shape. We have employed them as biofriendly sensors to translate the chin movement during speaking to language and to monitor the perfusion rate of a pig kidney. The FTENGs have offered excellent comfortability to the users and can play a vital role in reframing the power structure to be compatible with IoTs.

In this paper, we present a new compact hydraulic linear actuator. The concept is developed to change the rolling piston diameter of an active air spring during usage. By doing so, the air spring can actively apply pressure and tension forces. The actuator is designed for small movements at high forces. It is insensitive to side forces, which are introduced by the bellows rolling on the rolling piston of the air spring. A diaphragm sealing is used to minimize friction. Hence a precise adjustment of small displacements at high dynamics is possible and the system is completely leakage-free. We describe the design and development of this actuator and show first measurement results from preliminary tests to show its functionality.

Solar Energy and Hydrogen (energy carrier) are possible replacement options for fossil fuel and its associated problems of availability and high prices which are devastating small, developing, oil-importing economies. But a major drawback to the full implementation of solar energy, in particular photovoltaic (PV), is the lowering of conversion efficiency of PV cells due to elevated cell temperatures while in operation. Also, hydrogen as an energy carrier must be produced in gaseous or liquid form before it can be used as fuel; but its‟ present major conversion process produces an abundance of carbon dioxide which is harming the environment through global warming. In search of resolutions to these issues, this research investigated the application of Thermal Management to Photovoltaic (PV) modules in an attempt to reverse the effects of elevated cell temperature. The investigation also examined the effects of coupling the thermally managed PV modules to a proton exchange membrane (PEM) Hydrogen Generator for the production of hydrogen gas in an environmentally friendly and renewable way. The research took place in Kingston, Jamaica. The thermal management involved the application of two cooling systems which are Gravity-Fed Cooling (GFC) and Solar-Powered Adsorption Cooling (SPAC) systems. In both systems Mathematical Models were developed as predictive tools for critical aspects of the systems. The models were validated by the results of experiments. The results of the investigation showed that both cooling systems stopped the cells temperatures from rising, reversed the negative effects on conversion efficiency, and increased the power output of the module by as much as 39%. The results also showed that the thermally managed PV module when coupled to the hydrogen generator impacted positively with an appreciably increase of up to 32% in hydrogen gas production. The results of this work can be applied to the equatorial belt but also to other regions with suitable solar irradiation. The research has contributed to the wider community by the development of practical, environmentally friendly, cost effective Thermal Management Systems that guarantee improvement in photovoltaic power output, by introducing a novel way to use renewable energy that has potential to be used by individual household and/or as cottage industry, and by the development of Mathematical Tools to aid in photovoltaic power systems designs.