Ice hockey helmet standards are employed to test ice hockey helmets to ensure that they mitigate the risk of traumatic brain injuries. These standards primarily reflect adult ice hockey players' anthropometrics and play styles; however, they may not address youth ice hockey players anthropometrics and play styles. This study created a youth helmet test protocol using head impact characteristics specific to the Learn to Play (5-8 years old) youth ice hockey age group environment. The youth helmet test protocol was compared to a general helmet test protocol with the head mass, shoulder mass, and impacting velocities modified to reflect real-world conditions. The dependent variables used in the study included peak resultant linear acceleration, peak resultant rotational velocity, peak resultant rotational acceleration, and maximal principal strain (MPS). Two-way ANOVA identified significant interactions between the test protocols and two helmets tested in this study. This was followed by ANOVA to test for significance across the levels of the independent variables followed by paired t-tests to identify significant differences between the test protocols for each dependent variable for the head to boards and shoulder to head condition (p<0.05). The only significant difference identified between the test protocols for the head to ice condition was linear acceleration. The paired t-tests identified significant differences between the two helmets for all dependent variables for the head to ice and head to boards conditions (p<0.05). The results from this study revealed that youth are being exposed to similar amounts of brain trauma when compared to adults for the head to ice event. The head to ice condition is one of the most common types of impact events in the Learn to Play age group supporting the need to consider a youth specific ice hockey helmet standard test. This study demonstrated that the CCM FL 500 provided better protection for youth ice hockey players, and helmet companies could employ similar technologies to better protect youth from the risk of brain injuries.

Custo e durabilidade ainda são os maiores impeditivos para a entrada das células a combustível no mercado de dispositivos usados para produção de eletricidade. Assim, o objetivo deste trabalho foi avaliar a durabilidade dos conjuntos eletrodo-membrana-eletrodo (MEAs) produzidos no IPEN pelo método de impressão à tela para uso em células a combustível do tipo PEM. Para tanto, foi necessário desenvolver um protocolo adequado de teste de durabilidade de longa duração, visando obter estimativas da taxa de queda do potencial elétrico da célula a combustível ao longo do tempo e, assim, fazer inferência a respeito do tempo de vida deste dispositivo. Os MEAs testados durante este estudo foram preparados pelo método de impressão à tela com catalisador de Pt/C comercial e membrana Nafion® 115. O aprimoramento do protocolo de teste de durabilidade de longa duração se deu pela escolha dos procedimentos a serem executados e pelo ajuste de alguns parâmetros de operação da célula a combustível, tais como temperatura da célula, fluxo de H2 e fluxo de O2. Para a análise dos dados obtidos com os testes, foram aplicados métodos estatísticos de ajuste de modelos e curvas de polarização. Além disso, amostras da camada catalítica de um dos MEAs utilizados nos testes de durabilidade de longa duração foram analisadas por meio de microscopia eletrônica de transmissão (MET) para serem comparadas com amostras da camada catalítica de um MEA de controle. Para se avaliar o desempenho global da célula a combustível do tipo PEM em operações de longa duração, um dos grandes desafios foi fazer a separação entre as componentes de perda de desempenho que são reversíveis das irreversíveis. As estimativas obtidas para a taxa de queda do potencial elétrico da célula a combustível ao longo do tempo variaram num intervalo de 108,19 a 318,15 &mu;V.h-1. Estes resultados podem ser considerados satisfatórios quando comparados com valores apresentados na literatura. Finalmente, as imagens obtidas por MET mostraram uma tendência de aumento no tamanho médio das partículas Pt em decorrência do tempo de operação dos MEAs, mas que não implicou numa queda significativa do desempenho das células a combustível do tipo PEM testadas. / Cost and durability still represent the major barriers to the entry of proton exchange membrane fuel cells (PEMFCs) in the market. Thus, the objective of this work was to assess the durability of membrane-electrode assemblies (MEAs) produced at IPEN through the sieve printing method to be used in PEMFCs. For this purpose, an adequate long-term test protocol was developed aiming to obtain estimates of the voltage decay rate and lifetime of the PEMFCs. In the preparation of the MEAs through the sieve printing method commercial Pt/C catalyst and Nafion® 115 membranes were used. In the development of the long-term test protocol some procedures were defined and the fuel cell operational parameters were adjusted, such as cell temperature, H2 and O2 flows. In the analysis of the data obtained from the tests, statistical methods and polarization curves were applied. Samples of the catalyst layer from a MEA used in a long-term test were compared with samples from a control MEA using a Transmission Electron Microscopy (TEM). To evaluate the overall performance of the PEMFCs in long-term operations, a major challenge was to make the separation between the components of performance loss that are reversible from the ones that are irreversible. The estimates for the voltage decay rate ranged from 110 to 318 &mu;V.h-1. These results can be taken as satisfactory when compared with values reported in the literature. Finally, there was an increase in the average size of Pt particles in the catalyst of the long-term tested MEA, as observed in the micrographs. However, this increase did not lead to a significant performance loss of the PEMFCs.

Custo e durabilidade ainda são os maiores impeditivos para a entrada das células a combustível no mercado de dispositivos usados para produção de eletricidade. Assim, o objetivo deste trabalho foi avaliar a durabilidade dos conjuntos eletrodo-membrana-eletrodo (MEAs) produzidos no IPEN pelo método de impressão à tela para uso em células a combustível do tipo PEM. Para tanto, foi necessário desenvolver um protocolo adequado de teste de durabilidade de longa duração, visando obter estimativas da taxa de queda do potencial elétrico da célula a combustível ao longo do tempo e, assim, fazer inferência a respeito do tempo de vida deste dispositivo. Os MEAs testados durante este estudo foram preparados pelo método de impressão à tela com catalisador de Pt/C comercial e membrana Nafion® 115. O aprimoramento do protocolo de teste de durabilidade de longa duração se deu pela escolha dos procedimentos a serem executados e pelo ajuste de alguns parâmetros de operação da célula a combustível, tais como temperatura da célula, fluxo de H2 e fluxo de O2. Para a análise dos dados obtidos com os testes, foram aplicados métodos estatísticos de ajuste de modelos e curvas de polarização. Além disso, amostras da camada catalítica de um dos MEAs utilizados nos testes de durabilidade de longa duração foram analisadas por meio de microscopia eletrônica de transmissão (MET) para serem comparadas com amostras da camada catalítica de um MEA de controle. Para se avaliar o desempenho global da célula a combustível do tipo PEM em operações de longa duração, um dos grandes desafios foi fazer a separação entre as componentes de perda de desempenho que são reversíveis das irreversíveis. As estimativas obtidas para a taxa de queda do potencial elétrico da célula a combustível ao longo do tempo variaram num intervalo de 108,19 a 318,15 &mu;V.h-1. Estes resultados podem ser considerados satisfatórios quando comparados com valores apresentados na literatura. Finalmente, as imagens obtidas por MET mostraram uma tendência de aumento no tamanho médio das partículas Pt em decorrência do tempo de operação dos MEAs, mas que não implicou numa queda significativa do desempenho das células a combustível do tipo PEM testadas. / Cost and durability still represent the major barriers to the entry of proton exchange membrane fuel cells (PEMFCs) in the market. Thus, the objective of this work was to assess the durability of membrane-electrode assemblies (MEAs) produced at IPEN through the sieve printing method to be used in PEMFCs. For this purpose, an adequate long-term test protocol was developed aiming to obtain estimates of the voltage decay rate and lifetime of the PEMFCs. In the preparation of the MEAs through the sieve printing method commercial Pt/C catalyst and Nafion® 115 membranes were used. In the development of the long-term test protocol some procedures were defined and the fuel cell operational parameters were adjusted, such as cell temperature, H2 and O2 flows. In the analysis of the data obtained from the tests, statistical methods and polarization curves were applied. Samples of the catalyst layer from a MEA used in a long-term test were compared with samples from a control MEA using a Transmission Electron Microscopy (TEM). To evaluate the overall performance of the PEMFCs in long-term operations, a major challenge was to make the separation between the components of performance loss that are reversible from the ones that are irreversible. The estimates for the voltage decay rate ranged from 110 to 318 &mu;V.h-1. These results can be taken as satisfactory when compared with values reported in the literature. Finally, there was an increase in the average size of Pt particles in the catalyst of the long-term tested MEA, as observed in the micrographs. However, this increase did not lead to a significant performance loss of the PEMFCs.

Wireless communication for biomedical equipment is rapidly improving with the invention of new technologies. Due to the absence of cables, wireless technology is a growing area of interest for biomedical applications. As technology advances, many gadgets are becoming smaller and more portable. Often, there is a need for these medical devices to transfer data in real-time. However, it is critical to recognize the special obstacles connected with the creation of novel products that need in-body to off-body communication. Unlike standard wireless communication scenarios, such as Wi-Fi or cellular networks, where data passes through the air; in-body to off-body communication occurs within or on the surface of the human body. Itis a significant technological challenge to provide dependable and secure communication inside the body’s dynamic and changing environment. The human body’s dielectric characteristics, attenuation, received power, transmitted power, and distance to the receiver must be considered when designing any wireless implantable device. In this thesis, we designed tests with a lossy medium that simulates the human body and a few test protocols that can facilitate the testing and development of wireless communications from in-body to off-body for a medical device intended to support pelvic muscle floor training. We designed the test protocols based on this application and safety requirements. These tests were then used to evaluate and compare two commercially available transceivers operating at 433MHz and 2.4 GHz.We created and implemented several experiments using the communication models. This thesis investigated the properties of a lossy medium in the context of electromagnetic signals in wireless communication. The tests included a study of connectivity, range, latency, and packet errors that occur during signal transmission across the medium. The findings indicate that BLE modules might be more favorable for future advances. The outcomes of this thesis can be utilized as a starting point for the future development of the intended application.BLE technology is distinctive largely by its low power consumption, which is critical for applications where energy efficiency is the main concern. Especially important in the context of IoT (Internet of Things) and wearable devices, where long-lasting battery life is required. Furthermore, BLE provides a more robust and standardized communication protocol, making it easy to integrate and compatible with a wide range of devices and platforms. While 433 MHz modules have advantages such as a longer range and simpler technology, BLE’s increased transmission rate capabilities and broad acceptance in current smartphones and tablets make it more adaptable for applications that require frequent data exchange and compatibility with consumer devices.

In this dissertation, studies of accelerated pavement testing have been discussed and the relative advantage of using the Model Mobile Load Simulator 3 (MMLS3) has been illustrated. A test protocol of using MMLS3 as a fatigue characterization tool has been proposed and validated by testing several Hot Mix Asphalt slabs. Data acquisition was performed with strain gauges placed in different directions under slabs in controlled environmental condition. Analysis of data showed the effect of wheel load on fatigue behavior of pavement in terms of strain history response, cracking and reduction of modulus. Performance curves showing relation between initial strain and failure loads were developed and were compared with the performance curves obtained from standard method. It has been shown that rutting related excessive permanent strain due to movement of particles under wheel path can affect fatigue performance of Hot Mix Asphalt pavement. Method of estimation of time dependent strain has also been developed to predict observed strain.

This master’s thesis project has been made in collaboration with Luleå University of Technology and client company ZEEKR to advance the knowledge about Augmented-Reality Head-Up Displays (AR-HUDs). The technological advancements being made in the automotive industry are rapidly moving forward, and the implementation of Head-Up Displays has been a hot topic and focal point of user safety and driving assistance discussions for the past couple of years.The earliest HUDs would only show static information (speedometer, speed limits, and other status information), but lately the implementation of Augmented Reality technology in HUDs can be seen in many flagship car brands. The projection technology has been improving drastically since the early versions, but despite this, many still believe the system to be only a gimmick that does not add real value to the user. In fact, many believe it has the opposite effect of its actual purpose: to aid the user in driving.  We have engaged in this project with ZEEKR to establish a guideline on what to have in mind when designing the interface for a system like this. Given ZEEKR’s market presence in China and Europe, we also explore cultural expectations and user interactions to balance satisfaction across markets. To summarize this into something concise, the following research questions have been shaped:  1. How can the design of an AR-HUD be tailored to meet the divergent cultural expectations of users in ZEEKR’s primary markets, China and Europe, while maintaining a cohesive user experience?  2. How can information be optimally presented on an AR-HUD to achieve a balanced cognitive workload for the driver?  As we progressed in the thesis, we gravitated towards a third research question which proved to also be of interest to ZEEKR. The research question emerged as:  3. How can AR-HUD systems be assessed resource efficiently while maximizing user  feedback?  The thesis follows an iterative, 4-phase process based on an Industrial Design Engineer’s workflow. Initially context was explored through user and stakeholder interactions, collecting qualitative and quantitative data. Then multiple HUD concepts were generated and tested. Three comprehensive user tests were conducted: a low-fidelity prototyping workshop, a medium-fidelity VR user test with digitally added HUD elements, and a high-fidelity VR user test with a Logitech G29 rig in a Unity game engine for interactive driving simulations.  Our findings, combined with academic research and expertise in interface design and user experience, are concrete design suggestions for the designing of AR HUD systems. The findings also show that the cultural differences between the two user groups were not a as big as anticipated, altough further testing is required to fully determine this. The resutls also include a standardized test-protocol built in Unity that ZEEKR can use for future testings. / Detta examensarbete har utförts i samarbete med Luleå tekniska universitet och ZEEKR för att öka kunskapen om Augmented Reality Head-Up Displays (AR- HUDs). De teknologiska framstegen inom fordonsindustrin rör sig snabbt framåt, och implementeringen av HUD:ar har varit en central punkt i diskussioner om användarsäkerhet och körassistans. De tidigaste HUD:arna visade endast statisk information, men på senare tid har augmented reality-teknologi implementerats i många ledande bilmärken. Projektionsteknologin har förbättrats drastiskt, men många anser att systemet bara är en gimmick som inte tillför något verkligt värde. Många anser faktiskt att det har motsatt effekt av sitt egentliga syfte: att hjälpa användaren vid körning.  Vi har engagerat oss i detta projekt med ZEEKR för att etablera en riktlinje för vad man ska ha i åtanke när man designar gränssnittet för ett system som detta. Med tanke på ZEEKR:s marknadsnärvaro i Kina och Europa utforskar vi också kulturella förväntningar och användarinteraktioner för att balansera tillfredsställelse över marknader. För att sammanfatta detta i något koncist har följande forskningsfrågor formulerats:  1. Hur kan designen av en AR-HUD skräddarsys för att möta de olika kulturella förväntningarna hos användare på ZEEKR:s primära marknader, Kina och Europa, samtidigt som man bibehåller en sammanhängande användarupplevelse?  2. Hur kan information presenteras optimalt på en AR-HUD för att uppnå en balanserad kognitiv arbetsbelastning för föraren?  När vi gick vidare med avhandlingen, drogs vi mot en tredje forskningsfråga som också visade sig vara av intresse för ZEEKR. Forskningsfrågan formulerades som:  3. Hur kan AR-HUD-system utvärderas resurseffektivt samtidigt som användarinsikterna maximeras?  Examensarbetet följer en iterativ process med fyra phasear baserad på en industridesigningenjörs arbetsflöde. Inledningsvis undersöktes kontexten genom interaktioner med användare och intressenter, och kvalitativ och kvantitativ data samlades in. Därefter genererades och testades flera HUD-koncept. Tre omfattande användartester genomfördes: en lågfidelitets-prototyp workshop, ett medelfidelitets- VR-test med digitalt tillagda HUD-element, och ett högfidelitets-VR-test med en Logitech G29-rigg i Unity-spelmotor för interaktiva körsimuleringar.  Våra resultat,i kombination med akademisk forskning och expertis inom gränssnittsdesign och användarupplevelse, utgör konkreta designförslag för utformningen av AR HUD-system. Resultaten visar också att de kulturella skillnaderna mellan de två användargrupperna inte var så stora som förväntat, även om ytterligare tester krävs för att fullt ut fastställa detta. Resultaten inkluderar också ett standardiserat testprotokoll byggt i Unity som ZEEKR kan använda för framtida tester.