Indiana University-Purdue University Indianapolis (IUPUI) / Gait analysis plays a major role in treatment of osteoarthritis, knee or hip replacements, and musculoskeletal diseases. It is extensively used for injury rehabilitation and physical therapy for issues like Hemiplegia and Diplegia. It also provides us with the information to detect various improper gaits such as Parkinson's disease, Hemiplegic and diplegic gaits. Though there are many wearable and non-wearable methods to detect the improper gate performance, they are usually not user friendly and have restrictions. Most existing devices and systems can detect the gait but are very limited with regards of diagnosing them. The proposed method uses two A201 Force sensing resistors, accelerometer, and gyroscope to detect the gait and send diagnosed information of the possibility of the specified improper gaits via Bluetooth wireless communication system to the user's hand-held device or the desktop. The data received from the sensors was analyzed by the custom made micro-controller and is sent to the desktop or mobile device via Bluetooth module. The peak pressure values during a gait cycle were recorded and were used to indicate if the walk cycle of a person is normal or it has any abnormality. Future work: A magnetometer can be added to get more accurate results. More improper gaits can be detected by using two PCBs, one under each foot. Data can be sent to cloud and saved for future comparisons.

No description available.

The demand for electric vehicles is ever-increasingand as such, there needs to be an efficient and easy way to chargetheir batteries. Aiming to simplify the use of chargers this reporthas tackled the challenge of developing a prototype for charginga Formula Student Electric Vehicle. This prototype was namedCharge Controller and is what a user will interact with whencharging the vehicle’s battery. In this project, a new architecturefor the charging process has been designed for both hardware andsoftware. Initial tests prove that the charging of the vehicle canbe done in a simple manner. The hardware has been designed,produced, partially assembled and partially tested. The softwarehas been tested using a development board which demonstratesthat the design works. / Efterfrågan på elfordon ökar ständigt och därför måste det finnas ett effektivt och enkelt sätt att ladda batterierna. För att förenkla användningen av laddare har man i denna rapport tagit sig an utmaningen att utveckla en prototyp för att ladda ett elfordon från Formula Student. Denna prototyp fick namnet Charge Controller och är det som användaren kommer att interagera med när fordonets batteri laddas. I detta projekt har en ny arkitektur för laddningsprocessen utformats för både hårdvara och mjukvara. De första testerna visar att laddningen av fordonet kan göras på ett enkelt sätt. Hårdvaran har konstruerats, tillverkats, delvis monterats och delvis testats. har testats med hjälp av ett utvecklingskort, vilket visar att designen fungerar. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

Polychlorinated biphenyls (PCBs) are a class of environmentally persistent halogenated organic compounds that were once used as stabilizers to improve the properties of a variety of materials such as lubricants, heat transfer fluids, paints, and caulking materials. PCBs are also capable of migration through processes such as spillage into soils, leaching into groundwater, and volatilization into the atmosphere. Although banned in 1979 over health concerns, PCBs persist in these materials to this day because they are resistant to biotic degradation and natural weathering processes. The wide variety of contaminated materials means that many existing treatment options cannot be used across all media. This research focuses on the adaptation of a reductive dehalogenation system for dechlorination of PCBs from machine oils, paints, sludges, and soils. The system utilizes magnesium, glacial acetic acid, and ethanol in order to remove the chlorine atoms from the biphenyl backbone, which is less toxic and can be broken down biotically. A treatment plan was devised for machine oil contaminated with PCBs, involving sorption of PCBs onto a column of super activated alumina followed by desorption into hexane and treatment of the hexane with magnesium and acidified ethanol to dechlorinate the PCBs. In a small-scale study, 98.5% of PCBs from an oil sample were sorbed to the column, and the PCBs that were subsequently desorbed were dechlorinated to below detectable levels within one day of magnesium and acidified ethanol treatment. Information from small-scale studies was used to design larger sorption columns intended for use at a field site. iv A field study was conducted to compare the effectiveness of two different treatment system pastes at removing PCBs from painted surfaces. These pastes were formulated with bulking and viscosity control agents in order to cling to vertical surfaces, and contained either acidified ethanol and magnesium (Activated Metal Treatment System, AMTS) or acidified ethanol only (Non-Metal Treatment System, NMTS). AMTS was capable of 64.8% average removal of PCBs from paint, while NMTS demonstrated 89.5% average removal but required a second step to dechlorinate the extracted PCBs. This system allows for treatment of surfaces without demolishing the structure. AMTS was also studied for in situ dechlorination of PCBs in soils, and NMTS enclosed in a polyethylene barrier was studied for extraction of PCBs from sludges. A two-step system was devised for the ex situ treatment of PCB-contaminated soils. Solvent extraction with ethanol or an ethanol/ethyl lactate cosolvent is followed by dechlorination using magnesium and glacial acetic acid. Studies included the optimization of extraction solvent, cosolvent ratio, cost, and reuse of magnesium or extraction solvent. Surface analysis of magnesium particles used in dechlorination showed a precipitate occluding part of the surface, which was thought to be a combination of magnesium ethoxide and magnesium hydroxide. This precipitate is thought to come from the reaction of magnesium ethoxide formed during the PCB dechlorination process with pore water extracted from the soil.

Polychlorinated biphenyls are a ubiquitous environmental contaminant that can be found today throughout the world in soils and sediments, lakes and rivers, and flora and fauna. PCBs have percolated throughout the food chain, so that almost every human being has a detectable amount of the contaminant within their blood stream. Existing remediation methods include incineration, dredging and landfilling, and microbial degradation, but all of these methods have drawbacks that limit their effectiveness as treatment options. Recently, the use of zero-valent metals as a means of reductive dechlorination has been explored. Using a combination of zero-valent magnesium and catalytic palladium, a successful bimetallic system capable of degrading PCBs has been created and optimized. Determining the mechanism for the reductive dechlorination has proven to be an arduous task, but experimental evidence has suggested three possible radical-type mechanisms for the use Mg/Pd specifically in methanol (as compared to aqueous systems). These possible mechanisms differ in the type of hydrogen species that replaces the chlorine atom on the PCB. Thermodynamic information has also aided in narrowing down which of the suggested pathways is most likely. It appears likely that the hydrogen involved in the dechlorination has the form of a "hydride-like" radical, which is a form of electron-rich atomic hydrogen. According to the literature, Pd catalysts create this species within the first few subsurface layers of the palladium in the presence of molecular hydrogen. Further work will be necessary to confirm that the "hydride-like" radical is actually the species involved in the dechlorination.

The objective of this research is to determine and develop a model that is capable of accurately measuring customer satisfaction for different industries and in particularly for the Printed Wiring Boards (PWB) Manufacturers. The new model will incorporate data not being collected or utilized by the survey method of determining customer satisfaction. The method used is a weighted average of satisfaction among several researched categories with percentages that accurately represent the relative importance of multiple facets of the PWB manufacturers customer satisfaction. A very common term in quality assurance is that "What is not measured accurately can not be evaluated or managed correctly," thus customer satisfaction is a very important aspect of any business, industry, or government. A satisfied customer will do more business and recommend it to other potential customers. Thus the business will grow and more revenues result. On the other hand, an unsatisfied customer will abandon the business and encourage more customers not to get involved with the same business so the business may decline and lose its market share and profitability. The categories that contribute to PWB customer satisfaction will be determined by conducting surveys among the leaders and best in the business of the PWB industry in addition to discovery of related articles that define the categories of the customer satisfaction for the PWB manufacturers. Once the categories are determined, the research concentrates on the weighting of the categories that most contribute to the PWB customer's satisfaction and a measure of satisfaction is derived. The model is easily applied to any other kind of PWB business or service industry. The model is based on empirical methods that will give an accurate measurement for the PWB customer's satisfaction. This in turn allows organizations the opportunity for improving customer satisfaction and increasing market share. The algorithm is based on characteristics deemed important by customers. Thus the customer satisfaction index can be computed and monitored on a regular basis without costly surveys. The major difference between this new model and the standard methods of determining customer satisfaction using the surveys is that this model will utilize data available with the proposals, sales, shipping, receiving, quality, engineering, manufacturing, and purchasing departments. The developed method to measure customer satisfaction utilizing internal data can be more cost effective, more accurate, can provide individual customer satisfaction scores, can measure whether or not these individual scores are statistically lower than the majority, and can provide satisfaction measures in real time none of which can be supplied by the survey method.

Load transients are prevalent in every electronic device including semiconductor memory, card readers, microprocessors, disc drives, piezoelectric devices, and digitally based systems. They are capable of producing voltage stress, introducing noise, and degrading device functionality. In order to avoid damage to the device, a feedback control loop is implemented with system compensation to regulate the output voltage deviations by the converter. Because designing compensation networks can be rather complicated, DC-DC converters with integrated feedback control topologies help minimize design time and complexity of converter compensation at the expense of design flexibility. This thesis widens the limitations of an integrated DC-DC converter with a stability optimization technique that utilizes the feedback network to create a phase boost centered at the bandwidth of the converter to increase the phase margin and improve its transient response. Ideal modeling verifies stability optimization while non-ideal modeling that introduces PCB parasitics to the control loop suggest an additional phase boost in the feedback network. Experimental data confirms this non-deal model for parasitic capacitances higher than calculated. The modified non-ideal model shows more accuracy compared to the experimental data which indicates that there may be PCB parasitics that is unaccounted for. Modeling the modified non-ideal model to high orders may yield more accuracy. This thesis gives both DC-DC converter and PCB layout designers insight and considerations into PCB effects on the stability of DC-DC converters and the optimization of integrated compensation.

With the potential to improve upon silicon (Si ) based power electronics exhausted, the push for improvement now lies with wide bandgap (WBG) materials like gallium nitride (GaN). With a larger bandgap, higher electron mobility, and higher electrical field strength than Si, GaN high electron mobility transistors (HEMTs) can have lower on-state losses and higher switching frequencies in a smaller package. This makes GaN HEMTs an attractive choice for compact, high efficiency power devices. However, the package designs used for Si cannot be used for GaN HEMTs, requiring novel, chip-scale designs that are optimized for low electrical parasitics and low thermal resistance. Recent Center for Power Electronics (CPES) research culminated in a printed circuit board-direct bonded copper (PCB-DBC) hybrid package to house a 650 V, 150 A GaN HEMT. Called the PCB-Interposer-on-DBC package, it utilizes a DBC for heat extraction while using vertical pin interconnects to minimize electrical parasitics. Previous work did not investigate the design's locations of expected failure or reliability. With thermally generated mechanical fatigue a consistent cause of electronics failure, it must be investigated for the design to move beyond the prototyping phase. Thermo-mechanical fatigue failure is the brittle fracture of bonds caused by thermally induced warpage. The thermal warpage is the consequence of the bonded package components having a coefficient of expansion (CTE) mismatch while being subjected to temperature changes during operation. Multiphysics simulation software have previously quantified the fatigue placed on bonds exposed to these cyclic conditions, with a common metric being the volume-averaged inelastic strain energy density gained per cycle (ΔWavg). ΔWavg can identify which bonds are subjected to the greatest amount of fatigue and will thus fail first, and then quantify the effect of design alterations on those vulnerable bonds. A common design alteration seen in solder ball packaging is adding a polymeric material that encapsulates the bonds. If the polymer has a CTE like that of the package substrates and an elastic modulus (E) exceeding 1 GPa, it constrains the thermal warpage and lowers bond fatigue. This thesis uses thermo-mechanical simulations to provide evidence on which bonds fail first in the package, and that material-based methods of fatigue reduction used in solder ball packing apply to this novel package. Chapter 1 explains how a desire to reduce the cost and increase the performance of electric vehicles led to the development of the PCB-Interposer-on-DBC design, and that the package's response to thermo-mechanical fatigue is unknown. The concepts of thermo-mechanical fatigue and using encapsulants to reduce it are established, along with how simulations are used to study said fatigue. Chapter 2 serves two purposes, the first being an explanation of the simulation settings and metrics used to establish the quality and assumptions used, and the second being a beginners guide on how to create these simulations. Chapter 3 identifies the most probable locations of initial package failure and identifies what encapsulants minimize ΔWavg on those locations. The sintered silver bond expected to fail first is the Internal Gate bond, and an encapsulant with the maximum possible E and 8 ppm/°C minimizes ΔWavg. The Sn60Pb40 bond expected to fail first is the External Source 4 bond and using an encapsulant with the maximum possible E and a CTE of 24 ppm/°C minimizes ΔWavg. While ΔWavg cannot determine which of the two bonds fails first as they are made of different materials, the Internal Gate is prioritized as it has a higher per-cycle fatigue and to prevent loss of the gate signal. Chapter 4 demonstrates how to perform a brief encapsulant study while ranking the expected cycles to failure when using four different encapsulant options. The first two options are to use no encapsulant or silicone gel. As the elastic modulus of silicone gels are too low to restrict or couple the thermally generated warpage, using silicone gel results in a ΔWavg comparable to using no encapsulant. The rigid encapsulant with the properties most like the optimal encapsulant identified for Internal Gate has the lowest ΔWavg¬ of the encapsulants tested. Guidelines are established for what properties an encapsulant must have to outperform said rigid encapsulant. This work uses simulations to provide evidence that encapsulant methods used in ball grid array (BGA) packaging to reduce fatigue apply to a novel GaN HEMT package. By identifying the first-failure locations of the package, establishing what existing encapsulant should be used, and what encapsulation it should eventually be replaced with, these results provide the groundwork for both experimental temperatures cycling and more complex simulations. Such work fills the gap in understanding the reliable lifetime and common failure mechanisms of the PCB-Interposer-on-DBC package. / Master of Science / In modern engineering, the cause of failure in a well-designed electronic device is typically not a single event. Rather, it is the culmination of many smaller events that each cause a minor amount of damage. This cycle of repeated, minor damage is called fatigue. When working with power or IC electronics, the most common type of fatigue occurs due to the device's changing temperature. Electronics undergo continuously changing temperatures due to the environment and their own energy losses, causing repeated cycles of heating and cooling. All materials expand upon heating and contract upon cooling , and the magnitude of this change is the coefficient of thermal expansion (CTE). Electronic devices are comprised of dissimilar materials, so disparate components will expand and contract at different rates. Holding these disparate materials together are bonds, which in the process of holding this warped structure together, also deform. This deformation causes permanent damage, which accumulates in the bonds until they break. As these bonds often serve as pathways for the electrical signal or heat extraction, their failure either degrades or breaks the electrical devices. While preventing bond fatigue is impractical, there are strategies to extend the operating lifetime. A common option used elsewhere is to encase the bonds with a polymer. If the polymer's properties are carefully selected, they can reduce the structural warpage, thereby reducing the fatigue on the bonds. Previous Center for Power Electronics (CPES) research has culminated in a new electronics device called the Printed Circuit Board-Interposer-on-Direct Bonded Copper package (PCB-Interposer-on-DBC package). While general trends suggest which bonds will fail first and what kind of polymers reduce fatigue, this information has not yet been confirmed. This thesis uses computer simulations to identify which bonds will likely fail first, and to provide evidence that existing methods for reducing fatigue are viable for this unique package. The simulations work by subjecting a 3D model to a cycle of heating and cooling, called a temperature cycle, and quantifying the damage sustained by the bonds for every cycle. Chapter 1 describes the relevant details leading to this package design, the importance of thermo-mechanical reliability in the design of electronics, and how to use simulation software to quantify reductions in bond fatigue. Chapter 2 explains how to set up these simulations and evaluate their quality. Chapter 3 identifies the initial locations of package failure and identifies what are the most optimal encapsulants to use. Chapter 4 identifies what existing encapsulant will maximize the package lifetime in experimental temperature cycling.

No description available.

The work is about developing an existing product in a company. The productis AnyBus Communicator used to connect two serial devices with differentindustrial network interfaces. The development involves combining theexisting product with a BLE-module and an antenna. Wireless technologyopens up various possibilities and plays a significant role in complexenvironments. Today, communication occurs through an Ethernet cable. Theproject's goal is to design a circuit for the BLE-module integrated into theproduct's PCB. The goal also includes presenting a choice of antenna and aplastic-type for antenna enclosure that can be used in future development ofthe product. The work began with the evaluation of the BLE-module, wherea communication test was performed to test the BLE-module's properties.Several tests were performed using Network Analyzer to select a suitableantenna from three different antennas. The antennas were tested with twodifferent types of plastic designed using Solidworks, to present a choice ofthe type of plastic to be used during all tests in the development process.Presenting an electrical schematic and PCB for the wireless AnyBusCommunicator was a goal of the project. Since it was impossible to combinethe BLE-module with the product in the same PCB, it was decided to designa separate circuit that illustrates how the BLE-module will be connected tothe product in the future. The project resulted in a proposal for both an antennaand a plastic-type. A prototype circuit has also been designed for the BLEmodule. The choice of antenna and plastic-type was based on the best valuewhen measuring return loss values. The type of plastic chosen will not be usedin the finished product but is a way to test antenna functionality against 3Dprinted plastics. This is considered to be a cheaper solution that gives a similarresult compared to the enclosure used in the product. A finished design of thecircuit board has been implemented. However, it could not be tested due tothe company having a difficult situation to produce ordinary circuit.Therefore, it can be concluded that the work had relevant proposals and wasa forward step in the development process. / Arbetet handlar om att utveckla en befintlig produkt på ett företag. Produktenär en AnyBus Communicator som används för att koppla upp två seriellaenheter som har olika industriella nätverksgränssnitt. Utvecklingen innebäratt kombinera befintliga produkten med en BLE-modul och en antenn. Idag sker kommunikationen med en Ethernet-kabel. Målet med projektet äratt designa en krets för BLE-modulen som skall integreras i produktens PCB.Målet omfattar också att presentera ett val av antenn och en plasttyp förantennkapsling som kan användas i framtida utvecklingen för produkten. Arbetet inleddes med utvärdering av BLE-modulen, där ettkommunikationstest utfördes för att testa BLE-modulens egenskaper. Ettantal tester genomfördes med hjälp av nätverksanalysator för att kunna väljaen lämplig antenn utav tre olika antenner. Antennerna testades med två olikaplasttyper som är designade med hjälp av Solidworks, för att senarepresentera ett val av plasttypen som skall användas under alla tester iutvecklingsprocessen. Att presentera ett elschema och PCB för den trådlösaAnyBus Communicator var ett mål för projektet. Eftersom det inte var möjligtatt kombinera BLE-modulen med produkten i samma PCB, bestämdes det attdesigna egen krets för BLE-modulen som illustrerar hur den skall kopplas tillprodukten i framtiden. Projektet resulterade i ett förslag både på en antenn och plasttyp. En prototypkrets har även designats för BLE-modulen. Antennens och plasttypens val baserades på bästa värde vid mätning avreturförlustvärden. Plasttypen som valdes kommer inte att användas i denfärdiga produkten, utan det är ett sätt att testa antennfunktionalitet mot 3Dprintade plast. Det anses vara en billigare lösning som ger ett liknande resultatjämfört med kapslingen som används i produkten. En färdig design påkretskortet har genomförts men kunde inte testats på grund av att företagethar en besvärlig situation att få in vanliga produktionskort i dagsläget. Därförkan slutsatsen dras att arbetet hade relevanta förslag och var ett steg iutvecklingsprocessen.