<p>The health and social care sector has a continuous growth in the use of information technology. With more and more information about the patient stored in different systems by different health care actors, information sharing is a key to better treatment. The introduction of the personal health record aims at making this treatment process easier. In addition to being able to share information to others, the patients can also take a more active part in their treatment by communicating with participants through the system. As the personal health record is owned and controlled by the patient with assistance from health care actors, one of the keys to success lies in how the patient can control the access to the record. In this master's thesis we have developed an access control model for the personal health record in a Norwegian setting. The development is based on different studies of existing similar solutions and literature. Some of the topics we present are re-introduced from an earlier project. Interviews with potential users have also been a valuable and important source for ideas and inspiration, especially due to the fact that the access control model sets high demands on user-friendliness. As part of the access control model we have also suggested a set of key roles for the personal health record. Through a conceptual implementation we have further shown that the access control model can be implemented. Three different solutions that show the conceptual implementation in the Indivo personal health record have been suggested, using the Extensible Access Control Markup Language as the foundation.</p>

<p>A measurement of the hydraulic turbine efficiency at the Vessingfoss hydro power station by the thermodynamic method has been attempted, but has not given the desired results. Two problems have been encountered. The high pressure side temperature measurements show an abnormal scatter resulting in standard deviations of sy=0.05ºC. The reason for the scatter may be temperature layers in the reservoir lake Nesjø. This theory has been investigated, but needs further work. The other problem has been the mechanical strength of the low pressure side collector probes. Two different collectors have been tried, and both have broken down. The second attempt was made with a collector design based on wire rope, which failed because the turnbuckles were under-dimensioned. With proper dimensions, this solution is interesting in the future, as it was easy to install and may contribute to lose collector weight. The relative turbine efficiency has been calculated based on pressures and levels measured during the thermodynamic test. An uncertainty analysis of the result has been carried out. The head loss has been calculated based on technical drawings of the penstock and loss coefficients from the literature.</p>

<p>A multi-reactor, multi-temperature, waste-heat driven biomass thermochemical converter is proposed and simulated in the process simulation tool Aspen Plus™. The thermochemical converter is in Aspen Plus™ integrated with a gas turbine power cycle and a combined fuel cell/gas turbine power cycle. Both power cycles are recuperative, and supply the thermochemical converter with waste heat. For result comparison, the power cycles are also integrated with a reference conventional single-reactor thermochemical converter, utilizing partial oxidation to drive the conversion process. Exergy analysis is used for assessment of the simulation results. In stand-alone simulation, the proposed thermochemical shows high performance. Cold gas efficiency is 108.0% and syngas HHV is 14.5 MJ/kg on dry basis. When integrated with the gas turbine power cycle, the proposed converter fails to improve thermal efficiency of the integrated cycle significantly, compared to reference converter. Thermal efficiency is 41.8% and 40.7%, on a biomass HHV basis, with the proposed and the reference converter respectively. This is despite superior cold gas efficiency for the proposed converter, and the gas turbine cycle is found not to be able to properly take advantage of the high chemical energy in the syngas of the proposed converter. When integrated with the combined fuel cell/gas turbine power cycle, the proposed converter significantly improves the thermal efficiency of the integrated cycle, compared to the reference converter. Thermal efficiency is 56.0% and 51.2%, on a biomass HHV basis, with the proposed and the reference converter respectively. The fuel cell is found to be able to take advantage of the high chemical energy in the syngas of the proposed converter, which is the main cause of increase in thermal efficiency. Operation of the proposed thermochemical converter is found to be feasible at a wide range of operating conditions, although low operating temperatures in the converter may cause problems at very high carbon conversion ratios.</p>

<p>This paper treats further development of the TEG injection process described in Bråthen (2007). An introduction to separation technology, conventional glycol regeneration and compact mixing is presented, as these are important parts of the alternative dehydration concept. Advantages, disadvantages and operational problems are pointed out, before the problems with the TEG injection process is described. Using hot stripping gas for regeneration of the TEG is one of the suggested improvements, but large glycol losses, large flow rates of stripping gas and oxidizing of glycol are found to be the consequences, thus making the alternative unfeasible. The only improvements used, are to use inline separators for the first separation stages and compact mixers for mixing of TEG and natural gas. A simulation model is developed using the simulation software HYSYS with the CPA EoS as fluid package. Both the absorption and the regeneration part of the process is modeled, and operational data from the Snøhvit LNG facility is used as reference. From simulations it is found that TEG injection requires about 50% more circulated TEG than conventional absorber dehydration to obtain the same water content in the dehydrated gas. The weight and volume of the absorption part of the process is however found to be considerably smaller than the operational process at the Kristin field in the Norwegian North Sea, thus partly compensating for the increased TEG circulation rate. Use of MEG and DEG instead of TEG for the injection concept is also simulated, but it is concluded that TEG is the best suited because of lower regeneration energy, lower absorbent loss and best dehydration performance for low to intermediate flow rates of stripping gas. MEG is found to be unsuited for dehydration because of very large losses of absorbent.</p>

<p>Abstract This dissertation has been produced during the spring semester of 2008 to serve to the requirements for the degree of “Master of Technology” at the Norwegian University of Science and Technology (NTNU). The thesis has been written at the department of Energy and Process Engineering, with supervision of Professor Helge I. Andersson from the Fluid Dynamics department. The thesis has the title “Computation of Impinging Gas Jets”, and aims to investigate the Impinging Jet Flow (IJF) problem presented in section[2] by means of Computational Fluid Dynamics (CFD). For the work of this thesis the commercially available program package of FLUENT 6.3, and Gambit 2.4 was used for all the simulation and geometry generation tasks. The specific IJF case treated in the thesis work, is the Single Round Nozzle (SRN ) IJF geometry explained in section[2.2] , and displayed in Figure 2.2 . The numerical simulations were carried out by means of 2D and 3D Reynolds Averaged Navier Stokes ( RANS) simulations , and Large Eddy Simulation (LES) with related theory described in the theory section[3]. The work with the simulations of this thesis can roughly be divided into two main components. Firstly there is the part comprising all tasks and operations involved in creating and running the simulations, about which relevant information is provided in section[4]. Secondly, there is the work involving all the tasks related to gathering, interpreting, and analyzing the yielded simulation results. These tasks and their results are mainly treated in sections[5 to 9]. Both numerical and experimental reference IJF cases were used in this thesis work. The reference cases were at first used to guide the beginning of the simulation effort (Figure 6.1). In the later stages of the thesis, the reference results were used to analyze and interpret the results of the thesis simulations. Overall the results from the RANS simulations of this thesis, are found to give good agreement with the reference simulations and experiments, within the limits of what can be expected from the RNG k-ε model which was used. The LES simulations on the other hand, proves to be far more demanding both computation wise, and in relation to issues concerning simulation preparations and setup. In addition the LES simulation is found to be outperformed by the RANS simulations in some regions of the IJF geometry. When analyzed, it is found that this is probably caused by an unfortunate combination of regions with low local mesh quality, and a quite mesh sensitive feature in the Sub Grid Scale model. Nevertheless the LES simulation is found to provide results of good agreement with experimental data in some of the most difficult regions to simulate on the IJF geometry. In this region the LES simulation is also found to outperform the RANS simulations.</p>

<p>In this work, a 23-1 designed experiment has been performed to evaluate the effect of selected operating conditions on PEMFC performance and durability. Relative humidity, clamping pressure and back pressure were studied at two levels for Gore MEAs and GDLs. Two replicated experiments were performed. An ON/OFF test cycle was used to accelerate degradation. Total duration of the tests, after a break in procedure suggested by Gore, was ten days. In addition to sampling of voltage and current response and ohmic resistance, effluents were manually sampled from both electrodes every 24 hours and analyzed. Experiments with low humidification levels showed inferior durability. The combination of high relative humidity (100 %), high clamping pressure (10 barg) and high back pressure (1.5barg) result in the best performance and the lowest degradation rate. Results indicate that relative humidity is important both for performance and durability. Generally, fluoride emission rates (FER) showed an increasing trend with time. Higher rates were observed at the cathode. For the experiment with low relative humidity (25 %), low clamping pressure (5 barg) and high back pressure (1.5 barg) FER was significantly higher compared to the other experiments. For all tests the sulfur emission rates (SER) are initial high. Rates are higher at the anode. For the experiment with high relative humidity, low clamping pressure and no back pressure, the SER was significantly higher than for the other experiments. The sustained high levels of sulfur are probably a result of sulfuric acid residue from production of the MEA and/or GDL. High humidification of gases appears to more effectively wash out the sulfur.</p>

<p>Security in Mobile ad-hoc networks (MANETs) is difficult because of its operating environment and its lack of a central control unit, making classical security measures inapplicable. MIDAS is a project funded by the European Commission which creates a "Middleware platform for developing and deploying advanced mobile services". It is important for MIDAS to find a middle ground where it provides reasonable security, while using little extra processing power and battery and remains easy to use. In this thesis we identify the vulnerabilities and security measures needed to secure MIDAS, while preserving usability. We approach this problem by analysing the MIDAS design and find similarities to other known systems. From the analysis we identify threats and ethical issues, and suggest security mechanisms that solve MIDAS specific problems. The resulting security mechanisms are described in detail and tied together to create four main configurations with increasing levels of security. The configurations can then be used by MIDAS developers to implement security in a consistent way. The results are specific to MIDAS, but issues, requirements and security building blocks can be used by other projects for applicable MANET problems.</p>

<p>Coal is the most common fossil resource for power production worldwide and generates 40% of the worlds total electricity production. Even though coal is considered a pollutive resource, the great amounts and the increasing power demand leads to extensive use even in new developed power plants. To cover the world's future energy demand and at the same time limit our effect on global warming, coal fired power plants with CO2 capture is probably a necessity. An Integrated Gasification Combined Cycle (IGCC) Power Plant is a utilization of coal which gives incentives for CO2 capture. Coal is partially combusted in a reaction with steam and pure oxygen. The oxygen is produced in an air separation process and the steam is generated in the Power Island. Out of the gasifier comes a mixture of mainly H2 and CO. In a shift reactor the CO and additional steam are converted to CO2 and more H2. Carbon dioxide is separated from the hydrogen in a physical absorption process and compressed for storage. Hydrogen diluted with nitrogen from the air separation process is used as fuel in a combined cycle similar to NGCC. A complete IGCC Power Plant is described in this report. The air separation unit is modeled as a Linde two column process. Ambient air is compressed and cooled to dew point before it is separated into oxygen and nitrogen in a cryogenic distillation process. Out of the island oxygen is at a purity level of 95.6% and the nitrogen has a purity of 99.6%. The production cost of oxygen is 0.238 kWh per kilogram of oxygen delivered at 25°C and 1.4bar. The oxygen is then compressed to a gasification pressure of 42bar. In the gasification unit the oxygen together with steam is used to gasify the coal. On molar basis the coal composition is 73.5% C, 22.8% H2, 3.1% O2, 0.3% N2 and 0.3% S. The gasification temperature is at 1571°C and out of the unit comes syngas consisting of 66.9% CO, 31.1% H2, 1.4% H2O, 0.3% N2, 0.2% H2S and 0.1% CO2. The syngas is cooled and fed to a water gas shift reactor. Here the carbon monoxide is reacted with steam forming carbon dioxide and additional hydrogen. The gas composition of the gas out of the shift reactor is on dry basis 58.2% H2, 39.0% CO2, 2.4% CO, 0.2% N2 and 0.1% H2S. Both the gasification process and shift reactor is exothermal and there is no need of external heating. This leads to an exothermal heat loss, but parts of this heat is recovered. The gasifier has a Cold Gas Efficiency (CGE) of 84.0%. With a partial pressure of CO2 at 15.7 bar the carbon dioxide is easily removed by physical absorption. After separation the solvent is regenerated by expansion and CO2 is pressurized to 110bar to be stored. This process is not modeled, but for the scrubbing part an energy consumption of 0.08kWh per kilogram CO2 removed is assumed. For the compression of CO2, it is calculated with an energy consumption of 0.11kWh per kilogram CO2 removed. Removal of H2S and other pollutive unwanted substances is also removed in the CO2 scrubber. Between the CO2 removal and the combustion chamber is the H2 rich fuel gas is diluted with nitrogen from the air separation unit. This is done to increase the mass flow through the turbine. The amount of nitrogen available is decided by the amount of oxygen produced to the gasification process. Almost all the nitrogen produced may be utilized as diluter except from a few percent used in the coal feeding procedure to the gasifier. The diluted fuel gas has a composition of 50.4% H2, 46.1% N2, 2.1% CO and 1.4% CO2. In the Power Island a combined cycle with a gas turbine able to handle large H2 amounts is used. The use of steam in the gasifier and shift reactor are integrated in the heat recovery steam generator (HRSG) in the steam cycle. The heat removed from the syngas cooler is also recovered in the HRSG. The overall efficiency of the IGCC plant modeled is 36.8%. This includes oxygen and nitrogen production and compression, production of high pressure steam used in the Gasification Island, coal feeding costs, CO2 removal and compression and pressure losses through the processes. Other losses are not implemented and will probably reduce the efficiency.</p>

<p>Sorption Enhanced Steam Methane Reforming (SE-SMR) is a novel way of reforming natural gas to high purity hydrogen gas with in-situ CO2 capture by the introduction of a CO2 sorbent. The process is carried out in two steps. In the first step, hydrogen is produced and CO2 is absorbed by the sorbent. In the second step, the sorbent is exposed to high temperature heat and the CO2 is released. For the reforming to run continuously, two bubbling fluidized beds(BFB), can be coupled, one working as a reformer and the other one as a regenerator of the CO2 sorbent. The reformer works at a temperature around 500˚C and the regenerator at around 900˚C. Once the reactions in the reformer are being carried out the reformer works at a near autothermal state due to the exothermic reaction between CO2 and the sorbent. The regenerator however needs to be continuously supplied with heat to maintain at least 900˚C and for the endothermic calcination reaction of the sorbent to be carried out. One of the ways of providing heat to the process is by internal heat exchanger tubes. The advantage of using heat exchanger tubes is that no extra gas is added to the gas already in the bed (used interchangeably with reactor), thus not disturbing the volumetric flow and gas composition of the bed. For sequestration purposes, if the gases within the bed are not disturbed by for example nitrogen, N2, they will be easier to separate and sequester. An analytical calculation of the energy balance of a calcination reactor with horizontal heat transfer tubes was carried out, and the necessary effect was found to be 14.02kW, which equates to a heat exchanger with 96 tubes in 8 rows, taking up 26cm height in the reactor. Transferring heat via exhaust gas through metal tubes does however not yield a high thermal efficiency. One way of improving the efficiency of the calcinator is burning fuel gas directly in the reactor. This will lead to a direct heat exchange between the exhaust gas and the sorbent. On the other hand will the direct burning with air as an oxidizer lead to high fractions of N2 in the reactor. Considering that the gas in question in this work is biogas, the release of CO2 from the combustion is technically carbon neutral. Calculations for the necessary heat exchanger surface area and combustion rate of methane for the in-reactor combustion alternative have been carried out analytically, and a model of the in-reactor combustion has been established. At first, a fully fluidized bed model with integrated methane combustion was planned. Due to limitations of the modeling program and conversations with experts on the scope of the work in relation to the time-frame of the thesis, which is more closely discussed in Appendix H, the problem was reduced to a fixed bed approximation with “black box” combustion of methane outside the reactor. A heat balance, dependent on the rate of calcination was applied in the finite element modeling program COMSOL Multiphysics, and the resulting temperatures in the reactor were examined on the basis of what kind of fuel gas was used. In the first case, upgraded biogas, or SNG(Sustainable Natural Gas) was used as fuel gas. SNG is ~100% CH4, and the biogas has a CH4 content of ~48%. From the model it was seen that the mean temperature of the bed with SNG was 1218K, or 945˚C, and with the biogas the temperature of the bed was 1248K, or 975˚C. The calcination rate was found to be from 72.5 to 86.3% of the optimum. The lower results might be due to the adiabatic flame temperature of the gas and/or the relatively low heat capacity of the gas.</p>

<p>There are two main ways of measuring particle emission from wood combustion. Firstly, particles can be sampled directly in the chimney. Secondly, a dilution tunnel can be used, thus cooling the flue gases parallel to diluting. The purpose of this work is to investigate the differences between both measurements and establish which is the best method to measure particle emission from wood combustion. The approach is to perform particle emission measurements in the chimney and in a dilution tunnel simultaneously during the combustion of wood in a small-scale appliance. Moreover, Flame Ionization Analysis will be carried out to understand the contribution of condensed organic compounds to the total particulate matter emission. The particle emission measured in the dilution tunnel was between 5 and 12 times higher than in the chimney. The more unfavourable combustion conditions, the larger the difference between both measurements was seen. The results also show a factor of about 2,5 between both particle emission measured in the stack and Total Hydrocarbon content in the flue gas and particle emission measured in the dilution tunnel, indicating that about 35 % of the hydrocarbons measured in the stack with the Flame Ionization Detector condense along the dilution tunnel accounting for approximately 85 % of the total particle emission found at this location.</p>