The development of a test apparatus for proton exchange membrane fuel cells is presented. The design of the prototype device is provided in detail along with a description of the apparatus. The evaluation of the functionality and effectiveness of the device included measurement of a polarization curve for a 5-cell, 1 kW stack. An effective test apparatus is imperative for stack performance testing, model evaluation, and investigation of new fuel cell technology. This apparatus was designed to measure and control the mass flow rates of the reactant gases, gas pressures, gas temperatures, gas relative humidity, stack temperature, stack current, and the coolant water flow rate. Additionally, the test apparatus can measure the stack voltage, coolant water resistivity, coolant water temperature change across the stack, and the coolant water pressure drop across the stack. The apparatus was shown to provide adequate control of all necessary variables for stack performance evaluation. / Master of Science

Currently, wind energy presents an excellent opportunity to satisfy the growing demand without the supply and environmental problems associated with conventional energy. The engineering in wind turbines is not fully mature. There are still phenomenon, particularly dynamic stall, that cannot accurately be modeled or controlled. Dynamic stall contributes to fatigue stress and premature failure in many turbine components. The three dimensionality of dynamic stall makes these structures unique for wind turbines. Currently, flow visualization of dynamic stall on a wind turbine rotor has not been achieved. These visualizations can reveal a lot about the structures that contribute to dynamic stall. Particle Image Velocimetry (PIV) is a powerful experimental technique that can take multiple non-intrusive flow measurements simultaneously of planar flow. Using high-speed cameras time resolved PIV can reveal the transient development of a given flow field. This technique is ideally suited to gain a better understanding of dynamic stall. A custom wind turbine is being built at the University of Waterloo to allow such measurements on the blade. A high speed camera is mounted on the hub and will take measurements within the rotating domain. Mirrors are used so that laser illumination rotates with the blade. The wind turbine will operate in controlled conditions provided by a large wind tunnel. High speed pressure data acquisition will be used in conjunction with PIV to get an understanding of the forces associated with the flow structures. Computational fluid dynamics was used to size the rotor within the wind tunnel. Laser based measurements required special considerations for stiffness. Many revealing experiments will be made possible by this apparatus. First, the flow structures responsible for the various forces can be identified. Quantitative measurements of the flow field will identify the development of the stall vortex. The quantified flow structures can be used verify and improve models. The high spatial resolution of PIV can map the three dimensional flow structure in great detail. The experimental apparatus is independent of the blade geometry, as such multiple blades can be used to identify the effect of blade geometry. Finally flow control research in the field of aviation can be applied to control dynamic stall.

Currently, wind energy presents an excellent opportunity to satisfy the growing demand without the supply and environmental problems associated with conventional energy. The engineering in wind turbines is not fully mature. There are still phenomenon, particularly dynamic stall, that cannot accurately be modeled or controlled. Dynamic stall contributes to fatigue stress and premature failure in many turbine components. The three dimensionality of dynamic stall makes these structures unique for wind turbines. Currently, flow visualization of dynamic stall on a wind turbine rotor has not been achieved. These visualizations can reveal a lot about the structures that contribute to dynamic stall. Particle Image Velocimetry (PIV) is a powerful experimental technique that can take multiple non-intrusive flow measurements simultaneously of planar flow. Using high-speed cameras time resolved PIV can reveal the transient development of a given flow field. This technique is ideally suited to gain a better understanding of dynamic stall. A custom wind turbine is being built at the University of Waterloo to allow such measurements on the blade. A high speed camera is mounted on the hub and will take measurements within the rotating domain. Mirrors are used so that laser illumination rotates with the blade. The wind turbine will operate in controlled conditions provided by a large wind tunnel. High speed pressure data acquisition will be used in conjunction with PIV to get an understanding of the forces associated with the flow structures. Computational fluid dynamics was used to size the rotor within the wind tunnel. Laser based measurements required special considerations for stiffness. Many revealing experiments will be made possible by this apparatus. First, the flow structures responsible for the various forces can be identified. Quantitative measurements of the flow field will identify the development of the stall vortex. The quantified flow structures can be used verify and improve models. The high spatial resolution of PIV can map the three dimensional flow structure in great detail. The experimental apparatus is independent of the blade geometry, as such multiple blades can be used to identify the effect of blade geometry. Finally flow control research in the field of aviation can be applied to control dynamic stall.

No description available.

Grease-lubricated journal bearings present a common challenge for construction equipment manufacturers in the world. The common design methodology is based on empirical data and has worked very well historically because the market and governments have accepted that bearings in construction equipment need frequent lubrication and exchange of worn parts. Legal and market requirements will soon demand lower environmental impact and increased machine efficiency. These requirements call for better methods of designing grease lubricated journal bearings. The goal of the outlined work was to develop better design methods for grease lubricated journal-bearing design used in heavy-duty construction equipment machines, in order to prolong life and lubrication intervals. The research approach of the project can roughly be divided into three phases: 1. Development of test apparatus and test methods for journal bearing studies. 2. Bench tests of grease lubricated journal bearing design. 3. Verification between bench tests and computer simulations. In the thesis the current state of the art in bearing design for construction equipment is discussed and summarized in the form of design guidelines. The suggested design steps are just a mean to get to the starting point of design. The simple guidelines do however serve a purpose when collected since most published bearing design guidelines are aimed at the bushing material or at continuously rotating bearings. The influence of housing, environment and load cases can not be ignored when designing a bearing. Long term field-testing and experience can not be replaced until better design criteria have been established. Paper A deals with the design of the bearing test apparatus that was built and evaluated. Comparisons between theoretical contact and contact elements in Finite Element program have been made and discussed in paper B. In paper C a replica technique for measuring wear of large field specimens was evaluated. A case study of bearing housing design was performed in paper D utilizing Finite Element program and then validated in paper E in the bearing test apparatus. The influence of grease groove design on bushing life was tested and evaluated in paper F. Wear simulation of a plain bushing has been performed with a Finite Element program and presented in paper G. / QC 20100930

A series of plate load tests were conducted at the experimental farm of the University of Pretoria. The test areas were levelled by means of three surface preparation methods namely, i) a thin layer of plaster of Paris; ii) a thin layer of well-graded sand and iii) by using only hand tools. In addition, a modified plate load test was designed to eliminate the effect of bedding errors that occur during these tests. Telescopic probes were used to measure the relative displacement at two points below the centre of the plate. The main objective of this research project was to first quantify the bedding errors that occur during plate load tests. Secondly, to evaluate the three different surface preparation methods used in plate load tests to achieve a levelled and smooth test surface, and lastly to evaluate the effectiveness of using telescopic probes in routine plate load tests to eliminate the effects of bedding errors. The stiffness values, determined from the vertical displacement of the plate, were compared with the internal stiffness values determined by means of the telescopic probes. All stiffness values were compared with continuous surface wave (CSW) measurements performed on the same material. The test apparatus, methods and results are discussed in this dissertation. To my / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Civil Engineering / unrestricted

Stillasittande arbete och medföljande dålig hållning har kommit att bli ett stort problem i samhället. Framskjutet huvud, så kallad FHP (Forward Head Posture), är ett vanligt exempel på dålig hållning som har starka kopplingar till nacksmärta. Produkten FixaSpine är ett smarthalsband vars funktion är att komma till rätta med problemen genom att påminna användaren att räta upp sin hållning. Då produkten i dagsläget är i prototypstadiet behöver en stor mängd testning göras för att utveckla sensorteknologi och mjukvara. För att kunna testa prototyper på ett kontrollerat sätt uppstår behovet av en testanordning. Olika grad av FHP och hopsjunken rygg behöver kunna återskapas och det behöver kunna ske upprepade gånger med precision. Testanordningen bör även kunna utföra en störningsrörelse som Fixaspine ska kunna ignorera. Arbetets syfte är att möjliggöra en systematiserad testning och utveckling av FixaSpines sensorteknologi och funktionalitet, genom att ta fram en mekanisk testanordning som kan simulera dåliga hållningar samt en störningsrörelse. Genom att kartlägga olika positioner och rörelsemönster vid dålig hållning tas ett underlag fram för en mekanisk testanordning. Koncept utarbetas, beräkningar för drivning och motorer utförs, och slutligen görs konstruktion och detaljutveckling. Den resulterande testanordningen kan inta positioner som efterliknar olika grad av framskjutet huvud, som mest motsvarande en hög grad av FHP (CVA 22°). Den kan även efterlikna olika grad av hopsjunken rygg som motsvarar en rotation av bröst korgen på mer än 15°. Anordningen kan lutas framåt mer än 30° för att utföra en störningsrörelse. Dessutom kan den åstadkomma en kombination av ovan positioner och rörelser. Anordningen drivs av linjära ställdon som kan programmeras efter behov. Genom att använda testanordningen som utvecklingsredskap kan felvariabler och brus som testning på människor annars medför undvikas. På så vis underlättar testanordningen utvecklingen av FixaSpine och bidrar i förlängningen till minskad nacksmärta. / The prevalence of poor posture as a consequence of sedentary work has become a major issue in today’s society. A common example of poor posture is the so-called Forward Head Posture (FHP), which has strong associations with neck pain. FixaSpine is a smart necklace attempting to correct these problems by reminding its users to improve their posture when necessary. As the product is currently in the prototyping stage, thorough testing has to be conducted so that its software and sensor technology can be further developed. However, testing prototypes in a controlled manner has proven difficult. Hence, there is a need for a test apparatus able to simulate poor posture repeatedly and with precision. This device should be able to achieve various degrees of FHP and hunched back. Furthermore, it should also be able to perform a disruptive movement that Fixaspine ought to ignore.  The purpose of the project is to facilitate the systematized testing and development of FixaSpine’s sensor technology and functionality, by developing a mechanical test device. By analyzing lateral photographs of poor postures, positions and movement patterns are mapped, and the prerequisites for a mechanical test device determined. Concepts are drawn up, calculations for motor loads are carried out, and the final design and mechanical construction developed.  The resulting test device can simulate positions with varying degrees of Forward Head Posture. It is capable of achieving a high degree of FHP (CVA 22°). The device can simulate different degrees of hunched back equivalent to a thorax rotation of more than 15°. In addition, the device can be tilted forward more than 30°, performing a disruptive movement. Furthermore, it can perform a combination of these positions and movements. The device is powered by linear actuators that can be programmed as needed. Using it as a development tool minimizes error variables and noise otherwise prevalent when testing on humans. Subsequently, this test device is able to facilitate the development of FixaSpine and ultimately contribute to reducing neck pain.