Fracture of the distal radius is one of the most frequent injuries, and it represents about 20% of all adults taken into emergency rooms. A number of studies suggest various methods to reduce the dislocation and to secure fragments of the distal radius. In this study, the Non-Bridging External Wrist Fixator System (NBX), a pre-market-released product manufactured by NUTEK Inc. was biomechanically assessed by comparing with the Universal Distal Radius System (Volar Plate Fixator: VPF), a market-released product manufactured by Stryker Co. The comparison was performed in several parameters, which were wrist motion, radial tilt angle, radial length, volar tilt angle, stiffness, and failure load. Five pairs of fresh human cadaver arms were used for this study. The wrists were tested to obtain x-ray images for 1 normal and 2 injury conditions (intact, fractured, and fixed), 2 load conditions (gravity only and torque applied), and 4 postural conditions (volar flexion, dorsiflexion, ulnar deviation, and radial deviation). These tests yielded 24 (3×2×4) x-ray images for each wrist, and the images were analyzed to obtain the data for each parameter. Although the results were not statistically significant in some conditions, NBX fixation limited wrist motion more than VPF fixation. This result can be explained not only by the difference in the ability of fixation, but also by the difference in the surgical trauma (NBX is less invasive than VPF). Furthermore, in the measurement of radial tilt angle, radial length, and volar tilt angle, NBX was more effective than VPF to reduce and secure the bone fragments of the distal radius. In destructive test, the NBX is less strong than VPF. However, NBX is strong enough to sustain the expected forces of daily activity.

abstract: Photovoltaic (PV) systems are one of the next generation's renewable energy sources for our world energy demand. PV modules are highly reliable. However, in polluted environments, over time, they will collect grime and dust. There are also limited field data studies about soiling losses on PV modules. The study showed how important it is to investigate the effect of tilt angle on soiling. The study includes two sets of mini-modules. Each set has 9 PV modules tilted at 0, 5, 10, 15, 20, 23, 30, 33 and 40°. The first set called "Cleaned" was cleaned every other day. The second set called "Soiled" was never cleaned after the first day. The short circuit current, a measure of irradiance, and module temperature was monitored and recorded every two minutes over three months (January-March 2011). The data were analyzed to investigate the effect of tilt angle on daily and monthly soiling, and hence transmitted solar insolation and energy production by PV modules. The study shows that during the period of January through March 2011 there was an average loss due to soiling of approximately 2.02% for 0° tilt angle. Modules at tilt anlges 23° and 33° also have some insolation losses but do not come close to the module at 0° tilt angle. Tilt anlge 23° has approximately 1.05% monthly insolation loss, and 33° tilt angle has an insolation loss of approximately 0.96%. The soiling effect is present at any tilt angle, but the magnitude is evident: the flatter the solar module is placed the more energy it will lose. / Dissertation/Thesis / M.S.Tech Engineering 2011

No description available.

Modified design of a planter to be attached to a mobile robot, was the main objective of this project. This research project was part of a larger project, called “Developing robotics assisted technology for farming”. The main motivation for this research project is the fact that mobile robot, is an electric powered vehicle with limited power and pulling force. Thus, a customized planter with a customized connection mechanism should be designed. Besides, it should require less draft force compared to existing planters so that it can be pulled by the mobile robot. The developed planter should have the same efficiency as the existing planters in seeding. To find the forces between soil engagement tool (disc coulter) and soil, experiments were designed and performed in the Linear Soil Bin at University of Saskatchewan. Disc and tilt angle of a disc coulter was changed and draft, vertical and side forces applied to it were measured to find the disc and tilt angle combinations that results in minimum draft force. Experiments showed that 7° disc angle and 25° tilt angle provides the least draft force compared to other disc angle and tilt angle combinations. Then, using the knowledge obtained from literature and the soil bin experiments, a planter was designed conceptually and in detail, based on the existing CNH planter. For further analyses computer modeling was performed. The whole planter was modeled in 3D, using SolidWorks. Stress analysis was performed in ANSYS Workbench to calculate safety factor of the designed parts. Two prototypes were fabricated and were attached to the mobile robot for field tests. Tests were performed in indoor settings to measure the total draft force required to pull developed planters. Draft force was very close to the value that was calculated in design stage. Results showed that an average of 460 N pulling force is required to pull one row planter for 50 mm depth of cut, which can be compared to n existing CNH corn planter that requires a pulling force of between 900 N to 1300 N. Seed drop accuracy and function of the developed planters in opening and closing a packed soil in presence of residue, were also observed in outdoor tests.

Finding the optimum inter-row spacing and installation tilt for tilted or ground mounted PV systems is a big issue in designing the large-scale PV systems. Increasing the array spacing leads to higher annual generated energy because of the reduced impact of row-shading, but on the other hand, it increases costs of land purchase/lease and wiring costs. Many compromises between performance and cost should be done to design an optimum large-scaled solar plant. One of the criteria in designing of solar power plants is reducing of LCOE, which reflects the cost of every unit of generated energy. Site locations have large impacts on the optimal design of pitch distance and title angles, but such impacts have not been studied extensively in the existing studies, so it is going to bridge this research gap in this thesis.   The main purpose of this research is to investigate the impact of climate conditions on the pitch distance and tilt angle for large-scale PV plant and finding the optimal pitch distance and tilt according to the least cost of production. The impact of climate and meteorological data on the self-shading loss and yield of energy are investigated through a simulation tool, which is PVsyst software here, in different tilt angles and distances between rows. The different climates can be considered by choosing site locations in different latitudes to cover all climate zones. Six cities in temperate climate, three cities in tropic climate and one city in polar climate have been selected. LCOE minimizing is a measure in finding the optimum tilt and pitch distance for a 1 MW solar system installed in different latitudes. In this study the type, size and cost of components have been assumed constant in different climate conditions. There is a wide range of variability in some economic indicators like interest rate and discount rate as well as the cost of land in different climates or even countries in the same climate; then to highlight the impacts of climate conditions on the optimal tilt and pitch distance, these parameters were assumed to be constant in this study.   The results show the optimal tilt of angles increases with getting far of equator in a range between 0° and 40° to capture more direct sunlight, and the optimal raw spacing grows in further locations to equator in a range between 4 m to 11 m to reduce self- shading loss. Moreover, the best module configuration for PV arrays (portrait or landscape) can be different in different climates.

No description available.

No description available.

Efektyvų saulės jėgainių veikimą labai lemia geografinė padėtis, nes Saulės spindulių srautas žemės paviršiuje pasiskirsto netolygiai. Lietuva yra vidutinio klimato juostos šiaurinėje dalyje, kur dažnas debesuotumas, rūkas, lietus, sniegas, įvairios kilmės dulkės, tai veiksniai lemiantys fotovoltinių sistemų efektyvumo sumažėjimą. Baigiamajame magistro darbe nagrinėjami saulės fotovoltiniai įrenginiai, gamybos technologijos, rūšys, pagrindinės charakteristikos, konstrukcijų montavimo ypatybės vidutinių platumų regionuose. Aptarta įvairių šalių patirtis eksploatuojant saulės jėgaines skirtingomis klimato sąlygomis. Išnagrinėti pagrindiniai veiksniai, lemiantys jėgainės našumą. Darbe analizuojamas sniego, dulkių, lietaus lašų poveikis fotovoltinių įrenginių charakteristikoms. Atlikus eksperimentinius tyrimus, vertinami patirti nuostoliai dėl atmosferinių veiksnių įtakos. Aprašyti tyrimų ir analizės metodai. Išnagrinėjus eksperimentinių tyrimų rezultatus, pateikiamos baigiamojo darbo išvados ir pasiūlymai. Darbą sudaro šešios dalys: įvadas, saulės energetikos srities literatūros apžvalga, tyrimams naudotos medžiagos, metodai ir aparatūra, tyrimų rezultatai ir jų aptarimas, išvados ir pasiūlymai, literatūros sąrašas. Darbo apimtis – 73 p. teksto be priedų, 63 pav., 4 lent., 41 bibliografinis šaltinis. / The efficiency of solar power plants is strongly influenced by geographic location, because the solar radiation flux on the surface is distributed very irregular. Lithuania is situated in a humid continental zone in the northern part, where is frequent cloud cover, fog, rain, snow, dust of various origins, these are the factors determining the efficiency of photovoltaic systems. The thesis deals with solar photovoltaic devices, manufacturing technology, types, main characteristics, structural features of mounting at medium latitude regions. Discussed the experience of different countries operating solar power plants in different climatic conditions. Analyzed the major factors affecting plant performance. This paper analyzes the impact of snow, dust, rain drops on the characteristics of solar photovoltaic equipment. After experimental study measured the efficiency and losses due to atmospheric factors. Described the research and analysis methods. After considering the experimental results, conclusions are presented. Structure: introduction, solar energy literature review, materials and methods used in research, results and discussion, conclusions, references. Thesis consist of: 73 p. text without appendixes, 63 pictures, 4 tables, 41 bibliographical entries.

Solkraft kan täcka hela jordens energibehov många gånger utan att släppa ut växthusgaser eller andra giftiga ämnen vid drift och räknas därför till en hållbar och förnyelsebar energikälla. Solkraft är därför en lämplig kandidat till att ersätta dagens ej hållbara fossilbaserade energisystem. Priset för solceller har sjunkit mycket de senaste åren. Samtidigt som Sverige och EU har som mål att minska koldioxidutsläpp ges både skattereduktion för såld överskottsel från solkraft och ett investeringsstöd. Därför kan det eventuellt vara lönsamt att installera solceller i Sverige trots begränsad solinstrålning. Det krävs att återbetalningstiden är rimlig för att privatpersoner skall bestämma sig att investera i solceller. Miljövinster är inte alls motiverande för privatpersoner enligt undersökningar. Därför bör solcellsanläggningar optimera och dimensioneras för maximal ekonomisk lönsamhet för att öka chanserna att investeringen blir av. Det här arbetet undersöker hur ett optimalt solcellssystem ska se ut ur ett ekonomiskt perspektiv för en bostadsförening bestående av 25 lägenheter i Mellansverige under olika ekonomiska förutsättningar. Störst fokus ligger på att analysera hur lutningsvinkeln förändrar resultatet. Elproduktionen hos olika konfigurationer av solcellsanläggningar simulerades fram. Dessa resultat ställdes mot byggnadens elanvändning för att beräkna hur mycket el som används till för att spara inköpt el och hur mycket som säljs för att utifrån det beräkna lönsamheten. Mest el produceras vid lutningsvinkeln 40° vilket ger marginellt mer än 30° som taket lutar. Det visar sig att lutningsvinkeln kan justeras för att öka lönsamheten men det är endast ett fåtal procent som mest. Skillnaden är som störst för små anläggningar som precis täcker baslasten för fastigheten. Bästa vinkeln för dessa mindre system är 45°. Det är svårt att motivera det dyrare montaget för att vinkla upp modulerna då taket redan lutar nära optimalt. Skillnaden mellan köpt och sparad el är liten om skattereduktion ges. Det är dock oklart hur länge skattereduktionen varar så det är därför säkrare att dimensionera utifrån sitt eget elbehov. Ett solcellssystem dimensionerat för att sälja mycket överskottsel skulle kunna bli en stor förlustaffär. Om solkraft får större plats i Sveriges elproduktion kan den ge upphov till högre globala koldioxidutsläpp beroende på vilket energislag den ersätter. Samtidigt tar det längre tid i Sverige jämfört med andra länder innan en solcell kan beräknas koldioxidneutral då det redan är mycket låga koldioxidutsläpp i Sveriges elmix kombinerat med relativt låg solinstrålning. Det innebär att solkraft ur ett miljöperspektiv är tvivelaktigt i Sverige. / Solar power is estimated to be able to cover the whole earths energy demand many times without releasing greenhouse gases or other pollutants while they operate and is therefore considered a renewable energy source. Solar power is therefore a suitable replacement to today’s fossil based energy systems. The cost for solar cells have decreased a lot in recent years. At the same time Sweden and the European Union have goals set for reducing the amount of carbon dioxide released so a tax reduction is given to those who sells overproduced electricity from solar power to the grid. This means it could eventual be profitable even in Sweden for installing solar power even though the sun doesn’t shine as much that close to the poles. It is suitable to install solar panels at buildings since it is the building and service sector that uses the most electricity in Sweden. It must be profitable for private investors before they make the choice to invest in solar panels. Environmental benefits are not as attractive for private investors. Should the solar arrays be optimized in such way that the profit is maximized the investment is more likely to occur. This paper examines how an optimal solar cell system should look like from a profitable perspective for a building with 25 apartments in the middle of Sweden under different economic conditions. Most focus is directed towards how the tilt angle affects the results. The electricity production of different configurations of solar panels was simulated. These results were then compared to the electricity demand for the building so the amount used for self-consumption and how much is sold to the grid could be calculated and from that calculate how profitable that system is. Most electricity is produced at the tilt angle of 40°, but marginally more than 30° which the roof is tilted. The difference between tilt angles are just a few percent at most. The difference is most noticeable when the system is just big enough to cover the base electricity demand. The best tilt angle for those systems are 45°. It is hard to advocate for more expensive mounting for bigger systems since the roof already is close to the optimal tilt angle. The value for saved and sold electricity is very close to each other if tax reduction is given. It’s however uncertain for how long tax reduction will last. It is much safer to size a solar array to cover the building’s electricity demand. It could be very costly to size a solar array which relies upon selling electricity with today’s economic condition. However, solar power is questionable in Sweden in an environmental perspective.

Different wave power technologies are in development around the world in different stages of prototype testing. So far only a few devices have been deployed offshore at full scale for extended periods of time. Little data is published about how these different devices perform. This thesis presents results from experiments with the full-scale offshore wave energy converters at the Lysekil research site on the Swedish west coast. The theories, experiments, measurements, performance evaluations and developments of the submerged transmission in the direct driven permanent magnet linear generator are in focus. The reciprocating submerged transmission fulfills the purpose of transmitting the absorbed mechanical wave energy through the capsule wall into the generator, while preventing the seawater from entering the capsule and reducing the life time of the converter. A measuring system with seven laser triangulation sensors has been developed to measure small relative displacements between piston rod and seal housing in the submerged transmission with excellent accuracy for the purpose of evaluating both functional behavior and successive wear in-situ. A method for calculating relative tilt angles, azimuth angles, differential tilt angles, and successive wear in the submerged transmission has been developed. Additional sensors systems have been installed in the converter enabling correlation and a thorough investigation into the operating conditions of the transmission and the converter. The thesis presents unique results from the measurements. A data acquisition system transmits the signals from the converter on the seabed to an onshore measuring station. Results are presented in time-, frequency- and the time-frequency domain. The results have given important information for further development of the submerged transmission, which is important to the survivability of the system. The thesis describes the status of research, and is a step that may influence future designs of wave energy devices for reaching survivability and a cost-effective renewable energy system. / <p>Published is a preprint version of the full text and should be combined by the errata.</p> / The Lysekil Wave Power Project