Properties and modeling of MFI membranes

The permeation properties of thin (<2µm) film MFI molecular sieve membranes have been studied in the present work and a model has been developed. The synthesis of such materials has been studied to a smaller extent. The films have been grown on graded a-alumina microfiltration filters using a seeding method. Scanning electron microscopy and x-ray diffraction were used in addition to permeation measurements for characterization of the materials. In particular, a simple and unique model describing single component permeation was developed. The model is a combination of simple and basic equations for permeation and adsorption. The important defect distribution of the membrane and the properties of the support are measured in separate experiments. The model is unique since it is accounting for the effect of defects and support on the permeation properties. The model can adequately describe the performance of various MFI membranes. The model indicates mass transfer limitations of the supports that strongly affect, for instance, permeance ratios. It was also found that these ratios are dependent on crystallographic orientation, film thickness and experimental conditions in addition to the amount of defects. Permeance ratios can thus only be used to compare membranes with similar morphology and tested under similar conditions. It was found that defects formed in thicker films. Membranes prepared on masked substrates were of higher quality than membranes prepared on unmasked substrates. MFI membranes with low and varying aluminum content with similar material properties, such as defect distribution and thickness, were evaluated with multi-component hydrocarbon isomers permeation. The silicalite-1 membrane showed a minimum in separation selectivity between two C6 isomers whereas the ZSM5 membrane showed an almost constant selectivity, independent of temperature, but with lower permeances. The effect of the calcination rate on the membrane quality was investigated for silicalite-1 membranes. Based on a number of permeation characterization techniques, the membrane quality was independent of the calcination rate. It was found that the permeation properties of membranes comprised of small crystals in several layers were different from membranes comprised of one layer of larger crystals, although the quality of the membranes was similar. ZSM-5 membranes with high aluminum content showed catalytic conversion of ethanol into diethylether and ethylene under simultaneous separation of the ethanol / water azeotropeGodkänd; 2004; 20061004 (bajo

MFI-molecular sieve membranes : synthesis, characterization and modelling

This work concerns evaluation by permeation measurements and modeling of thin (<2µm) MFI molecular sieve membranes and, to a smaller extent, synthesis of such materials. The membranes have been synthesized on graded a-alumina microfiltration filters using The seed film method. Scanning electron microscopy and x-ray diffraction were used for characterization in addition to permeation measurements. Mathematical models describing membrane flux for real membranes and defect distributions were developed. Defect distributions were calculated from porosimetry data and were further used for prediction of single gas permeation characteristics for real membranes. The models confirm the experimental findings, with respect to ideal selectivities as a measurement of membrane quality. Membrane permeation simulations indicate increasing ideal selectivities, with increasing film thickness, for quotients containing SF6. Thereby a high quality membrane could possess low ideal selectivities. This finding was confirmed by comparing experimental data of several membranes with varying thickness. The correlation between multi component separation data and commonly used quality criteria was investigated. It was found that commonly used single gas permeation quotients (ideal selectivity) between light inorganic gases, especially those containing sulphurhexaflouride (SF6), is less appropriate for membrane quality measurement. The porosimetry experiment showed on the other hand a good agreement between experimental data and separation performance of the membranes, as expected. ZSM-5 membranes with low aluminum content and silicalite-1 membranes with similar material properties, such as defect distribution and thickness were evaluated with multi component hydrocarbon isomers permeation. The ZSM-5 membrane had lower permeances and a slightly better butane isomer separation performance than the silicalite-1 membrane. The latter membrane showed a minimum in separation selectivity between two C6 isomers whereas the ZSM-5 membrane showed an almost constant selectivity, independent of temperature, but with lower permeances. ZSM-5 membranes with a high aluminum content catalyzed the formation of diethylether and ethylen at temperatures exceeding 150°C from a water/ethanol mixture. The membrane separated a mixture of C4 isomers with good performance at elevated temperatures. However these membranes suffered from temperature instability problems.Godkänd; 2002; 20070224 (ysko

Design and construction of a permeation measurement equipment

This project started due to the need for a permeation test facility at the division of chemical technology at Luleå University of technology. The project covers design, equipment selection and construction of the test facility. A permeation measurement testing system was constructed consisting of several components, which is capable of making advanced measurements of the permeation characteristics on different gases and liquids. The system will be automated by a computer system once routine tests are started. The system contains three main components: one gas chromatograph one tubular split type furnace and a heated zone. The heated zone contains evaporating units and pressure regulating equipment. Quantitative gas analysis of the retentate and permeate will be performed with the gas chromatograph, in order to evaluate separation characteristics of the membrane. Several limitations had to be made regarding temperature, pressure and other operating parameters in order to find appropriate equipment and keep costs manageable. Within these limitations, all equipment was ordered and mounted together into the permeation test facility.Validerat; 20101217 (root

Förbättring av Unreal Engine-renderingar med hjälp av Generativa Motståndarnätverk

Game engines such as Unreal Engine 5 are widely used to create photo-realistic renderings. To run these renderings at high quality without experiencing any performance issues,high-performance hardware is often required. In situations where the hardware is lacking,users may be forced to lower the quality and resolution of renderings to maintain goodperformance. While this may be acceptable in some situations, it limits the benefit that apowerful tool like Unreal Engine 5 can provide. This thesis aims to explore the possibilityof using a Real-ESRGAN, fine-tuned on a custom data set, to increase both the resolutionand quality of screenshots taken in Unreal Engine 5. By doing this, users can lower theresolution and quality of their Unreal Engine 5 rendering while still being able to generatehigh quality screenshots similar to those produced when running the rendering at higherresolution and higher quality. To accomplish this, a custom data set was created by randomizing camera positionsand capturing screenshots in an Unreal Engine 5 rendering. This data set was used to finetune a pre-trained Real-ESRGAN model. The fine-tuned model could then generate imagesfrom low resolution and low quality screenshots taken in Unreal Engine 5. The resultingimages were analyzed and evaluated using both quantitative and qualitative methods.The conclusions drawn from this thesis indicate that images generated using the finetuned weights are of high quality. This conclusion is supported by quantitative measurements, demonstrating that the generated images and the ground truth images are similar.Furthermore, visual inspection conducted by the authors confirms that the generated images are similar to the reference images, despite occasional artifacts

Förbättring av Unreal Engine-renderingar med hjälp av Generativa Motståndarnätverk

Game engines such as Unreal Engine 5 are widely used to create photo-realistic renderings. To run these renderings at high quality without experiencing any performance issues,high-performance hardware is often required. In situations where the hardware is lacking,users may be forced to lower the quality and resolution of renderings to maintain goodperformance. While this may be acceptable in some situations, it limits the benefit that apowerful tool like Unreal Engine 5 can provide. This thesis aims to explore the possibilityof using a Real-ESRGAN, fine-tuned on a custom data set, to increase both the resolutionand quality of screenshots taken in Unreal Engine 5. By doing this, users can lower theresolution and quality of their Unreal Engine 5 rendering while still being able to generatehigh quality screenshots similar to those produced when running the rendering at higherresolution and higher quality. To accomplish this, a custom data set was created by randomizing camera positionsand capturing screenshots in an Unreal Engine 5 rendering. This data set was used to finetune a pre-trained Real-ESRGAN model. The fine-tuned model could then generate imagesfrom low resolution and low quality screenshots taken in Unreal Engine 5. The resultingimages were analyzed and evaluated using both quantitative and qualitative methods.The conclusions drawn from this thesis indicate that images generated using the finetuned weights are of high quality. This conclusion is supported by quantitative measurements, demonstrating that the generated images and the ground truth images are similar.Furthermore, visual inspection conducted by the authors confirms that the generated images are similar to the reference images, despite occasional artifacts

Accurate measurement of the thermal expansion of MFI zeolite membranes by in situ HTXRPD

Template removal by calcination of MFI type membranes is often accompanied by crack formatìon. The thermal behavior of MFI type membranes, synthesized with and without masking, was studied to understand the mechanìsm. Masking prevents growth of zeolite in thè interior of the support during membrane synthesis. Rietveld refìnements of powder diffraction data collected in situ at high temperature allowed to accurately determine the change in thermal expansion of thè MFI film and thè porous a-alumìna support. During heating, a relatively large contraction of the celi volume during template removal occurred in thè zeolite powder and in thè film of thè membrane prepared with masking. The much smaller decrease in thè non-masked sample indicates that this membrane is under stress during heating and as a consequence, cracks are formed. The stress imposed in the membrane prepared without masking may be due to the opposite thermal behavior of the substrate in combination with strong bonds between thè membrane and thè support

TopQ - en webbaserad köapplikation : En fallstudie i utvecklingen av en köapplikation för studenter och handledare med fokus på navigering och design

Students’ learning processes can be affected negatively by long waiting times to get assistance on lesson- and lab-sessions. Studies show that digital queuing systems decrease the waiting time. Thus, the purpose of this report is to investigate how to design a web-based queuing application to achieve a high perceived usability for students and tutors. Especially based on navigability and design which in accordance with research in the area has a direct impact on the usability. To achieve a high perceived usability the application was developed iteratively. In the first version the implemented functionality was built upon the result from the feasibility study combined with research in the area. After a set of user evaluations, changes from the first version were implemented to further improve the perceived usability. Lastly, another set of evaluations were performed to confirm the improvement in the final version. The results showed that the first version of the system was perceived as 84 out of 100 on the System Usability Scale (SUS) and the final version as 88 out of 100, an improvement by four units. Uniform design, no irrelevant functionality, placing buttons in conspicuous positions and having double checks to “dangerous actions” all seem to be factors contributing to the navigability, desirability and thus the usability on a queuing-application.Studenters lärandeprocess kan påverkas negativt av långa väntetider för att få hjälp under lektions- och laborationspass. Studier visar att digitala kösystem reducerar väntetiden. Följaktligen är syftet med arbetet att undersöka hur en webb-baserad köapplikation kan designas för att uppnå en hög upplevd användbarhet hos studenter och handledare. Speciellt med avseende på navigerbarhet och design vilket enligt tidigare forskning har en direkt påverkan på användbarheten. För att uppnå en hög upplevd användbarhet utvecklades applikationen iterativt. I den första versionen implementerades funktionalitet som byggde på resultatet från förstudien i kombination med tidigare forskning. Efter användartester implementerades ändringar från den första versionen för att ytterlige förbättra användbarheten. Slutligen genomfördes ytterligare användartester för att bekräfta förbättringen i den slutgiltiga versionen. Resultatet visade att den första versionen av systemet uppfattades som 84 av 100 på systemanvändbarhetsskalan SUS och den slutgiltiga som 88 av 100, en förbättring med fyra enheter. Enhetlig design, ingen irrelevant funktionalitet, placering av knappar i iögonfallande positioner och att ha kontroller vid “farliga klick” verkar alla vara faktorer som bidrar till navigerbarheten, åtråvärdheten och där med användbarheten för en kö-applikation