The breakthrough in mobile technology and the development of smartphones, supplied with sensing devices such as Inertial Measurement Units (IMUs), has made it possible to obtain accurate and reliable data on the angular velocity for different objects. The available technical sensors for wrist movements, such as electrogoniometers, are costly, time-consuming, and need a particular computer program to be analyzed. Therefore, there is a need to develop user-friendly risk assessment methods for wrist angular velocity measurements. This master thesis aimed to validate the accuracy of a newly developed iPhone application (App), "ErgoHandMeter," for wrist velocity in actual work tasks, by comparing the “ErgoHandMeter” to standard electrogoniometers. The project study was performed with four participants, two females and two males, from three jobs performing actual work tasks. The total angular velocity obtained by the mobile application was compared with the angular velocity data from the standard electrogoniometer. The total angular velocities obtained from the smartphone and the goniometer were computed at the 10th, 50th and 90th percentile for the four subjects. The 50th percentile of goniometer-flexion velocity (G-flex) was 7.4 ± 5.4°/s, for the goniometer-total (G-tot) 8.7 ± 6.5)°/s and for App 7.2 ± 4.9°/s. The correlation coefficient for the 50th percentile of goniometer-flexion (G-flex) parameter and smartphone application was 0.994. For the goniometer-total (G-tot) and the application, it was 0.993. In a Bland-Altman plot the mean difference between G-flex and App for the 50th percentile was -0.18 °/s and for G-tot and App was -1.54 °/s, i.e. the App was lower in average. The limit of the agreement between G-Flex and App, and G-tot and App stayed within two standard deviations. For G-Flex and App (mean+1.96SD) was 1.34 °/s, (mean-1.96SD) was -1.71 °/s, while for G-tot and App (mean+1.96SD) was 1.89 °/s, (mean-1.96SD) was -4.96 °/s, indicating an adequate agreement between the two methods. A limitation was that the included occupations were all relatively low velocity. However, in conclusion, the results indicate that the two methods agree adequately and can be used interchangeably. / Genombrottet inom mobiltekniken och utvecklingen av smarttelefoner med sensorer som t.ex. tröghetsmätningsenheter (IMU) har gjort det möjligt att få exakta och tillförlitliga uppgifter om vinkelhastigheten för olika objekt. De tillgängliga tekniska sensorerna för handledsrörelser, t.ex. elektrogoniometrar, är dyra, tidskrävande och de samplade signalerna kräver ett särskilt datorprogram för att analyseras. Det finns därför ett behov av att utveckla användarvänliga riskbedömningsmetoder för mätningar av handledens vinkelhastighet. Syftet med detta examensarbete var att validera noggrannheten hos en nyutvecklad iPhone-applikation (App), "ErgoHandMeter", för handledshastighet i verkliga arbetsuppgifter, genom att jämföra "ErgoHandMeter" med vanliga elektrogoniometrar. Projektstudien genomfördes med fyra deltagare, två kvinnor och två män, från tre yrken som utförde verkliga arbetsuppgifter. Den totala vinkelhastigheten som erhölls av mobilapplikationen jämfördes med vinkelhastighetsdata från standardelektrogoniometern. De totala vinkelhastigheterna som erhållits från smarttelefonen och goniometern beräknades vid den 10:e, 50:e och 90:e percentilen för de fyra försökspersonerna. Den 50:e percentilen för goniometer-flexionshastigheten (G-flex) var i genomsnitt 7,4°/s och för goniometertotalen (G-tot) 8,7°/s. Korrelationskoefficienten (r) för den 50:e percentilen för goniometer-flexionsparametern (G-flex) och smartphone-applikationen var 0,994. För goniometer-total (G-tot) och applikationen var r 0,993. I en Bland-Altman-plot var den genomsnittliga skillnaden mellan G-flex och appen för den 50:e percentilen -0,18°/s och för G-tot och appen -1,54°/s (App var lägre än Gon). Medelvärdet för differensen mellan G-Flex och App och G-tot och App ligger inom två standardavvikelser. För G-Flex och App (medelvärde+1,96SD) var 1,34 °/s, (medelvärde-1,96SD) var -1,71 °/s, medan för G-tot och App (medelvärde+1,96SD) var 1,89 °/s, (medelvärde-1,96SD) var -4,96 °/s. Vilket tyder på en tillräcklig överensstämmelse mellan de två metoderna. En begränsning var att de inkluderade yrkena alla hade relativt låg hastighet. Sammanfattningsvis visar dock resultaten att de två metoderna stämmer väl överens och kan användas på ett utbytbart sätt.

Belastningsskador hos arbetare är ett ökande problem hos olika företag och det har visat sig finnas en tydlig koppling mellan dessa skador och handledens vinkelhastigheten. Det är därför av stort intresse att kunna mäta dessa vinkelhastigheter på ett noggrant och smidigt sätt. Syftet med denna rapport är att utvärdera precisionen av IMU-sensorers förmåga att beräkna vinkelhastigheten av handleden. Detta görs genom att jämföra data från IMU-sensorer med data från ett optiskt spårningssystem (OTS), vilket klassas som en gold standard inom detta område. Ett experiment bestående av åtta övningar utfördes: tre standard rörelser (flexion och rotation i takterna 40, 90 och 140 slag per minut) och fyra simulerade arbeten (målning, pappersvikning, datorarbete och hårföning). Grad av överensstämmelse ges av 1,96 standardavvikelser (SD) för standardrörelserna (10 deltagare) vilka var -31,8 grader/s och 34,2 grader/s, medan för de simulerade arbetena var det -35,1 grader/s och 34,2 grader/s. Det lägsta medelvärdet av medelkvadratavvikelse (RMSD) var 15,7 grader/s och erhölls vid 40 BPM medan den högsta medelvärdet var 93,9 grader/s och erhölls vid målningsövningen. Medelvärdet av korrelationskoefficienten mellan IMU-sensorer och OTS varierade mellan 0,97 och 0,42 och korrelationskoefficienterna av deltagarnas 50:e percentiler av vinkelhastigheten var 0,95 för standardrörelserna och 0,96 för de simulerade arbetena. Medelvärdet av absoluta differensen mellan sensorer och OTS var givet i percentiler (10:e, 50:e och 90:e). Det största spannet för 50:e percentilen gavs vid 140 BPM (18,3 ± 24,6) och det minsta spannet vid 40 BPM (3,5 ± 4,7). Trots att det fanns mindre differenser mellan metodernas mätningar av vinkelhastighet, anser vi att IMU-sensorer har potential att användas för att mäta vinkelhastigheter hos handledens och med vidare utveckling kan den nuvarande differensen minimeras. / Musculoskeletal disorders (MSDs) are increasingly frequent amongst workers and there is a clear connection between work injuries and wrist angular velocities. One of the biggest issues therefore is the currently limited availability of means to measure these angular velocities. The aim of this study is to validate the usability of the IMU sensors to measure angular velocities. This is done by comparing the data from the IMU:s with the data obtained with the optical motion tracking system (OTS), which is considered gold standard within this field of studies. An experiment consisting of eight exercises was conducted: three standard movements (flexion and rotation in the pace 40, 90 and 140 repetitions per minute) and four simulated practical work tasks (painting, folding paper, computer exercise and using a hairdryer). The limits of agreement for the standard movements (10 subjects) were -31,8 degrees/s and 34,2 degrees/s, whereas for the simulated practical work tasks they were -35,1 degrees/s and 28,2 degrees/s. The lowest mean value of the root mean square deviation (RMSD) value was 15,7 degrees/s which represents the 40 BPM task whilst the highest mean value was 93,9 degrees/s which correspond to the painting task. The mean value of the correlation coefficients between the IMU:s and the OTS ranged between 0,97 and 0,42 and the correlation coefficient between the subjects 50:th percentiles of the angular velocity, was 0,95 for the standard movements whilst for the practical work tasks it was 0,96. The mean value of the absolute difference between the sensors and the OTS was given in percentiles (10th, 50th and 90th). The largest range within the 50th percentile occurred during the 140 BPM task (18,3 ± 24,6) and the smallest range during the 40 BPM task (3,5 ± 4,7). Although the measured angular velocities vary to a certain extent between the two methods, we conclude that the IMU sensors present the potential to work as measuring units for wrist angular velocities and with further development the current differences can be minimized. / Forte dnr: 2017-01209 "Enkel och tideffektiv metod att mät, analysera och presentera biomekaniskbelastning för hand-handled"

Объектом исследования являются медь и малолегированные бронзы, подвергнутые интенсивной пластической деформации. Целью работы было определение текущего состояния научных исследований по использованию меди и малолегированных бронз. А также предложить состав и исследовать структуру и свойства бронзы выбранного состава после интенсивной пластической деформации методом динамического канально-углового прессования. В процессе работы проводился анализ литературных источников. В результате исследования было установлено текущее состояние по проблематике работы и определен вектор исследований. Методами оптической металлографии, дюрометрического анализа, просвечивающей электронной микроскопии и сканирующей электронной микроскопии с применением дисперсионно-энергетического анализа и анализа на основе обратного рассеяния электронов было проведено исследование сплава Cu-0,8 вес.% Hf. При различных обработках методом динамического канально-углового прессования. Эксперимент включал различное состояние бронзы перед деформированием. Также было проведено исследование термической стабильности полученных методом динамического канально-углового прессования образцов. Было установлено, что гафниевая бронза после прессования обладает высокими механическими характеристиками и ультрамелкодисперсной структурой. При этом полученная структура стабильна при комнатной температуре и при последующем отжиге вплоть до 400 °С. Что позволяет рекомендовать данный материал как основу для широкого спектра электротехнических изделий. / The object of research is copper and low-alloy bronzes after severe plastic deformation. The purpose of this work was to review scientific research on the use of copper and low-alloy bronzes. As well as the development of the composition and study of the structure and properties of bronze after severe plastic deformation by the method of dynamic channel-angular pressing had been carried out. Literature analysis was carried out. Methods of optical metallography, durometric analysis, transmission electron microscopy and scanning electron microscopy using energy dispersion analysis and analysis based on electron backscattering had been used to study the Cu-0.8 wt.% Hf alloy. Various processings had been carried out by the method of dynamic canal-angular pressing. The state of the bronze before deformation was variouse. We also studied the thermal stability of samples obtained by the method of dynamic channel-angular pressing. It was found that hafnium bronze after pressing has high mechanical characteristics and an ultrafine structure. In this case, the resulting structure is stable at room temperature and upon subsequent annealing up to 400 °C. That allows us to recommend this material as a basis for a wide range of electrical products.

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No description available.

Since the dawn of the space race, satellites have grown rapidly in complexity and shrunk equally rapidly in size. Most of them contain an Attitude Determination and Control System (ADCS) on board for pointing and detumbling manoeuvres. These intricate systems are designed for an outer space environment, hence, phenomenon otherwise abscent in space, such as gravity and aerodynamic drag present a challenge in validating these systems on Earth. The gimbal suspension testbed aims to provide a 3 Degree of Freedom (DoF) suspension where the mounted satellite under test can rotate about either axis. The suspension induces disturbance torques that must be modeled in order for the testbed to be characterized. This is accomplished by formulating the necessary gimbal dynamics, bearing friction, aerodynamic and Center of Mass (CoM) displacement torque model. This yields a relationship from which all torques present in the system can be expressed in terms of the angles, angular velocities and angular accelerations of the gimbal frames. By measuring the angles and obtaining the velocities and accelerations through numerical differentiation, the torques that correspond to a certain motion can be calculated. Furthermore, the thesis covers the iterative design of the gimbal suspension and all of its constituents, the angular measurement method and a Finite Element Method (FEM) simulation to estimate deformations. The result is presented in terms of a simulation that validates the models by predicting its behaviour for certain movement. The final result is a series of characterization plots that tells the user of the gimbal testbed how much torque must be produced by the CubeSat ADCS in order to operate it. / Sedan begynnelsen av rymdkapplöpningen har satelliter snabbt ökat i komplexitet och lika snabbt minskat i storlek. De flesta satelliter har ett attitydsbestänings- och kontrollsystem (ADCS) ombord för att kunna utföra vissa manövrar. Dessa system är designade för rymdmiljön, därför kan fenomen som annars är frånvarande i rymden, så som gravitation och luftmotstånd, innebära en utmaning då man önskar att validera systemet på jorden. Gimbalupphängningen förmedlar rotation med tre frihetsgrader där satelliten under test kan rotera kring alla tre axlar. Upphängningen inducerar störmoment som måste modelleras för att den ska bli ordentligt karaktäriserad. Detta åstadkoms genom att formulera gimbalens dynamiska förhållanden, kullagerfriktion, luftmotstånd och masscenterförflyttning. Dessa samband kopplar samman alla moment som är närvarande i systemet som funktion av gimbalramarnas vinklar, vinkelhastigheter och vinkelaccelerationer. Genom att mäta vinklarna och erhålla vinkelhastigheter och vinkelacceleration genom numerisk derivering kan momenten som motsvarar den uppmätta rörelsen beräknas. Dessutom presenteras den iterativa designen av gimbalupphängningen och alla dess beståndsdelar, vinkelmätningsmetoden och en finita elementmetodssimulering för att uppskaffa deformationer. Resultatet presenteras i form av simuleringar som validerar modellen genom att förutspå dess beteende för viss rörelse. Det slutgiltiga resultatet är en serie av karaktäriseringsgrafer som förmedlar till användaren just hur mycket moment dess CubeSats ADCS måste producera för att kunna använda gimbalupphängingen.

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In an extensive outdoor propagation study, low antenna heights of 1.7 m are used at both the transmitter and the receiver to measure over 3500 wideband power-delay profiles (PDPs) of the channel for a peer-to-peer communications system. Rural and urban areas are studied in 22 different transmitter-receiver links. The results are used to characterize the narrowband path loss, mean delay, root-mean-square (RMS) delay spread, and timing jitter of the peer-to-peer wideband channel. Small-scale fading characteristics are measured in detail by measuring and analyzing 160 PDPs within each local area. This thesis shows the measurement setup for the calculation of fading rate variance and angular spread and reports the first known attempt to calculate angular spread from track power measurements. New analysis presented in this thesis shows the effect of measurement error in the calculation of angular spread. The expected characteristics of angular spread are derived using two different angle-of-arrival (AOA) models from the literature. Measurement results show initial validation of Durgin's angular spread theory. A new measurement-based algorithm for simulating wideband fading processes is developed and implemented. This simulation technique shows promise in the simulation of high-bit rate peer-to-peer radio communication systems. / Master of Science

The betavoltaic battery is a type of micro nuclear battery that harvests beta emitting radioactive decay energy using semiconductors. The literature results suggest that a better model is needed to design a betavoltaic battery. This dissertation creates a comprehensive model that includes all of the important factors that impact betavoltaic battery output and efficiency. Recent advancements in micro electro mechanical systems (MEMS) necessitate an onboard miniaturized power source. As these devices are highly functional, longevity of the power source is also preferred. Betavoltaic batteries are a very promising power source that can fulfill these requirements. They can be miniaturized to the size of a human hair. On the other hand, miniaturization of chemical batteries is restricted by low energy density. That is why betavoltaics are a viable option as a power source for sophisticated MEMS devices. They can also be used for implantable medical devices such as pacemakers; for remote applications such as spacecraft, undersea exploration, polar regions, mountains; military equipment; for sensor networks for environmental monitoring; and for sensors embedded in bridges due to their high energy density and long lifetime (up to 100 years). A betavoltaic battery simulation model was developed using Monte Carlo particle transport codes such as MCNP and PENELOPE whereas many researchers used simple empirical equations. These particle transport codes consider the comprehensive physics theory for electron transport in materials. They are used to estimate the energy deposition and the penetration depth of beta particles in the semiconductors. A full energy spectrum was used in the model to take into account the actual radioactive decay energy of the beta particles. These results were compared to the traditional betavoltaic battery design method of estimating energy deposition and penetration depth using monoenergetic beta average energy. Significant differences in results were observed that have a major impact on betavoltaic battery design. Furthermore, the angular distribution of the beta particles was incorporated in the model in order to take into account the effect of isotropic emission of beta decay. The backscattering of beta particles and loss of energy with angular dependence were analyzed. Then, the drift-diffusion semiconductor model was applied in order to estimate the power outputs for the battery, whereas many researchers used the simple collection probability model neglecting many design parameters. The results showed that an optimum junction depth can maximize the power output. The short circuit current and open circuit voltage of the battery varied with the semiconductor junction depth, angular distribution, and different activities. However, the analysis showed that the analytical results overpredicted the experimental results when self-absorption was not considered. Therefore, the percentage of self-absorption and the source thickness were estimated using a radioisotope source model. It was then validated with the thickness calculated from the specific activity of the radioisotope. As a result, the battery model was improved significantly. Furthermore, different tritiated metal sources were analyzed and the beta fluxes were compared. The optimum source thicknesses were designed to increase the source efficiencies. Both narrow and wide band gap semiconductors for beryllium tritide were analyzed. / PHD / A betavoltaic battery is a type of micro nuclear battery that harnesses electrical energy from radioisotopes using semiconductors. It has high specific energy density and longevity but low specific power. It can be miniaturized to a micron scale size (a size of a human hair) to power micro/nano sensors or devices. They can be used in implantable biomedical devices such as pacemakers, remote areas such as high mountains, undersea, and also in embedded sensors in structures. Chemical and other types of batteries are not suitable at this scale due to their low specific energy density. A betavoltaic battery is an attractive choice in applications where reliability and long service life (up to 100 years) are required. However, their power output is very low (on the scale of microwatts) due to their low specific power. They can aid chemical batteries to increase their lifetime by designing a hybrid battery. In a hybrid battery, a betavoltaic battery can trickle charge a chemical battery to top off the depleted charge. A theoretical analysis of a battery design is useful to improve its power output and efficiency. The literature in this area suggests that a better theoretical model is required to agree well with the experimental results as well as for better design. This model comprehensively included all the important factors that impact betavoltaic battery output and efficiency. All the necessary betavoltaic battery design factors were analyzed in detail in this work in order to maximize the desired output.

Bei der internen, extramedullären Osteosynthese des distalen Femurs, auf die sich diese Arbeit fokussiert, haben sich in den letzten Jahren interessante Entwicklungen vollzogen. Ausgehend von unzufriedenstellenden Komplikationsraten wurden neue Wege in der Versorgung dieser schwierigen Frakturen gesucht. Osteosynthesematerialien, Repositionstechniken, die Technik der Implantatplatzierung und die Implantate selbst, bei denen die Entwicklung zu winkelstabilen Systemen gegangen ist, haben sich grundlegend geändert. Die vorliegende Arbeit analysiert in einer retrospektiven Studie distale Femurfrakturen, die zwischen dem 1.1.1995 und 31.9.2000 entweder mit einem Fixateur interne (LISS) oder mit der konventionellen Plattenosteosynthese versorgt wurden. In die Studie konnten 51 Patienten mit 54 distalen Femurfrakturen eingeschlossen werden. Die Infektionsrate war in der LISS-Gruppe (0% versus 11,1%) nichtsignifikant geringer, die Rate der verzögerten Frakturheilungen war nichtsignifikant höher. Die einzige verzögerte Frakturheilung (LISS-Gruppe), die einer sekundären chirurgischen Intervention bedurfte, wurde bei einer Patientin mit einem großen Knochendefekt gesehen, der ohne primäre Spongiosaplastik therapiert worden war. Pseudarthrosen traten in beiden Gruppen nicht auf. Die Rate des Materialversagens unterschied sich nicht signifikant. Beim LISS kam es nicht, wie bei den konventionellen Implantaten zu sekundären Repositionsverlusten, es wurden aber im Anfang der klinischen Einführung proximale Schraubenausrisse aufgrund einer Fehlplatzierung gesehen. Es konnte gezeigt werden, dass es durch die Verwendung des LISS und die indirekten Repositionstechniken zu keiner Zunahme der Achsfehlstellungen oder der Operationszeit kam. Die funktionellen Einzelergebnisse und die Punktzahl der erhobenen Scores (Neer-Score und Lysholm-Score) unterschieden sich nicht signifikant. / Internal, extramedullary osteosynthesis of distal femoral fractures which are focussed on in this study has been influenced by interesting developments in recent years. Driven by unsatisfying complication rates new fracture treatments have been looked for. Osteosynthesis materials, reduction techniques, techniques of implant placement and implants themselves - where development went to angular stable systems - have changed decisively. This study analyzes in a retrospective setting distal femoral fractures which were treated between 1.1.1995 and 31.9.2000 either with an internal fixator (LISS) or with conventional plate osteosynthesis. In this study 51 patients with 54 distal femoral fractures could be included. The Infection rate was non significantly lower in the LISS group (0% versus 11,1%), the rate of delayed union was non significantly higher. The only delayed union in the LISS group which needed secondary surgical intervention was seen in a patient with considerate bone loss which was not treated by primary bone grafting. Non-unions were not seen in either group. The rate of implant failure did not differ significantly. In the LISS group no secondary loss of reduction (like in the group with conventional plate osteosyntesis) was seen but proximal screw pull out due to malplacement was reported in the beginning of clinical introduction. It could be demonstrated the LISS and indirect reduction leading not to a higher rate of malalignement nor to prolonged theatre times. Functional results and the point score of the Neer Score and the Lysholm Score showed no significant difference.