The goal of the project was to characterize the granular flows impact on the gas flow in a packed-bed-reactor. The study was created at Swerim as a master's thesis for Luleå University of Technology. The packed-bed-reactor geometry used in this study is a scaled down blast furnace model. The granular flow was modelled using the discrete element method (DEM) in LS-DYNA. Four models were created with different sizes and size distribution of the particles. To study the granular flows impact on gas flow, porosity is extracted from the DEM models and analyzed, since porosity has a direct impact on the gas flow. The supervisors form Swerim, Joakim Eck and Martin Flemström created computational fluid dynamics (CFD) models in Ansys Fluent using the porosity from the DEM models. The DEM results are presented as granular flow profiles. This flow profile is created by injecting particles with alternating colors to see this profile. A total of 6 images are taken over the whole process. The porosity results are presented as a porosity field plots of the extracted porosity data using MATLAB. The CFD results are presented as plots of gas velocity and absolute pressure. The results show the different characteristics of the flow in the different DEM models, and how it relates to the different porosity fields that were found. Furthermore, the CFD models show how the flow of the gas is dependent on the porosity.

Evaluation of influence of interpolation methods on coregistration of radar images Abstract SAR interferogram processing requires subpixel coregistration of SAR image pair for accurate phase differencing. Errors in alignment introduce phase noise in SAR interferogram. Last step in coregistration is resampling one of SAR images. Also this step introduces errors in SAR interferogram. The resampling algorithms Nearest Neighbor, Bilinear interpolation, Cubic Convolution and advanced methods such as Raised Cosine kernel, Knab interpolation kernel and Truncated Sinc were tested on ERS tandem data and compared. The results were compared with the theory and simulations of earlier investigations (Hanssen, Bamler, 1999), (Migliaccio, Bruno, 2003) and (Cho ... [et al.], 2005). The main experiment in this work was to examine and compare resampling methods on real data to evaluate their effect on the interferometric phase quality and DEM generation. The coregistration performance was evaluated by the coherence (Touzi ... [et al.], 1999) and the sum of phase differences (Li ... [et al.], 2004). No evidence showed that computationally intensive algorithms produced better quality of interferogram than Cubic Convolution. The possibilities of evaluating by means of the accuracy of the final InSAR DEM (Li, Bethel, 2008) were...

When operating hydraulic mining excavators the loading equipment is exposed to harsh conditions which lead to extensive wear of the equipment, especially the bucket and bucket teeth. Simulations are used to better understand the wear development and to evaluate new methods to operate excavators more efficiently. At the Aitik mine, operated by the high-tech metal company Boliden Mines, hydraulic excavators are used when loading the mined ore. One of the hydraulic excavators used at Aitik is the Komatsu PC7000. In this master thesis, a simulation model for the hydraulic excavator Komatsu PC7000 was developed with the simulation software LS-DYNA. This model consists of multi rigid body dynamics to describe the motion of the excavator and a granular material model to describe the rocks loaded into the bucket of the excavator. Simulations with two different types of granular material models have been utilized to study the wear development of the bucket. One of the models (bonded DE model) uses bonded discrete elements to describe the large rocks and single discrete elements are used to describe smaller rocks. This model is compared to the current FE-DE model which is being used today at Boliden. This model uses finite elements (FE) to model the larger rocks and discrete element spheres (DES) for smaller rocks. By using the bonded DE method a 71\% reduction in simulation time could be achieved. This can be partly explained by the reduction of the number of elements included in the rock pile.  Archard's wear law was used to numerically describe the wear development of the bucket. When simulating the wear a total of 30 bucket fillings were performed with the excavator. This was done with both the bonded DE method and the FE-DE method. In this wear study, the inside of the bucket was of interest. The resulting simulated wear map was compared to experimental measurements from which the plate thickness of the bucket had been measured two times to obtain the wear depth of some points inside the bucket. The experimental measurements and two 3D scanned point clouds were used to determine the wear depth inside the bucket. Results from the simulation showed that the wear is concentrated to the center of the bucket while less wear is concentrated to the sides of the bucket. With the bonded DE method the wear appeared to be more evenly distributed inside the bucket while the wear from the FE-DE method appeared in spots inside the bucket. The experimental results also showed that the wear was more extensive in the center of the bucket and also in the back of the bucket. Both simulation methods also showed that the wear was concentrated to the back of the bucket. From the simulations, it was also seen that the behavior of the material flow differed between the two methods. In the bonded DE method the material flow had more sliding behavior while the material flow in the FE-DE method had more rolling behavior. This could also be the reason why the bonded DE method captures the wear more evenly. The rolling behavior seen in the FE-DE method leads to more impact wear which is not captured by Archard's wear law. Overall, the bonded DE method leads to a big reduction in simulation time which is favorable when it comes to simulation. The larger rocks will have simpler shapes without sharp corners. However, the method allows for a more complex shape than just an ordinary sphere which is the simplest and most common shape to describe granular material. The bonded DE method also allows for easier configuration of contact definition since fewer contact interfaces must be added to the model. Furthermore, the post-processing of wear in LS-DYNA was facilitated since the wear does not have to be divided into two wear collectors for FE elements and DE elements.

Läromedel i religionskunskap på gymnasiet kan vara problematiska att använda. Religionerna hinduism och buddhism framställs ofta som österländska religioner som avviker från den västerländska religiösa normen. Likaså brister många läromedel i genus- och jämställdhetsperspektiv. Detta examensarbete har som syfte att analysera hur hinduism och buddhism framställs i tre läromedel i religionskunskap på gymnasiet i både text- och bildmaterial. Undersökningen utgår från postkolonial teoribildning och ett genus- och jämställdhetsperspektiv. Jag analyserar om det finns orientalistiska tendenser i framställningarna om hinduism och buddhism och om kvinnor och män får lika stort utrymme samt hur respektive kön framställs. Resultatet visar att hinduism och buddhism framställs utifrån ett eurocentrisk och kristocentrisk perspektiv. Båda religionerna är utsatta för exotifiering och romantisering. Det finns även ett tydligt vi- och dem-perspektiv i framställningarna av religionerna. Resultatet visar också att läromedlen i kapitlen om hinduism och buddhism inte ger män och kvinnor lika stort utrymme och att mannen ofta framställs som normen som kvinnan mäts gentemot. Berättelsen om kvinnan blir en tilläggskategori då hon inte ingår i den generella beskrivningen av religionen. Män porträtteras också i högre utsträckning i bildmaterial och skildrar ett helighetsideal medan kvinnor i större utsträckning utför vardagssysslor. Slutsatsen är att samtliga tre läromedel i någon grad innehåller orientalistiska tendenser och att de brister i genus- och jämställdhetsperspektiv.

Fine-scale resolution digital elevation models (DEMs) created from data collected using high precision instruments have become ubiquitous in fluvial geomorphology. They permit a diverse range of spatially explicit analyses including hydraulic modeling, habitat modeling and geomorphic change detection. Yet, the intercomparison of survey technologies across a diverse range of wadeable stream habitats has not yet been examined. Additionally, we lack an understanding regarding the precision of DEMs derived from ground-based surveys conducted by different, and inherently subjective, observers. This thesis addresses current knowledge gaps with the objectives i) to intercompare survey techniques for characterizing instream topography, and ii) to characterize observer variability in instream topographic surveys. To address objective i, we used total station (TS), real-time kinematic (rtk) GPS, terrestrial laser scanner (TLS), and infrared airborne laser scanning (ALS) topographic data from six sites of varying complexity in the Lemhi River Basin, Idaho. The accuracy of derived bare earth DEMs was evaluated relative to higher precision TS point data. Significant DEM discrepancies between pairwise techniques were calculated using propagated DEM errors thresholded at a 95% confidence interval. Mean discrepancies between TS and rtkGPS DEMs were relatively low (≤ 0.05 m), yet TS data collection time was up to 2.4 times longer than rtkGPS. ALS DEMs had lower accuracy than TS or rtkGPS DEMs, but ALS aerial coverage and floodplain topographic representation was superior to all other techniques. The TLS bare earth DEM accuracy and precision were lower than other techniques as a result of vegetation returns misinterpreted as ground returns. To address objective ii, we used a case study where seven field crews surveyed the same six sites to quantify the magnitude and effect of observer variability on DEMs interpolated from the survey data. We modeled two geomorphic change scenarios and calculated net erosion and deposition volumes at a 95% confidence interval. We observed several large magnitude elevation discrepancies across crews, however many of these i) tended to be highly localized, ii) were due to systematic errors, iii) did not significantly affect DEM-derived metric precision, and iv) can be corrected post-hoc.

Since 2013, the shootings in Sweden have increased, and during the year 2020 the country reached a new peak in the amount of shootings according to the police. So far, during 2021, 109 shootings have occured in the area of Stockholm, 20 of which have included deaths, and 35 people have been injured. Since the start of the study, on the 31st of October 2021, nine people had been shot to death in the area of Järva. In addition, every tenth shooting that has taken place in Sweden since 2018 has been located in Järva. This study examines how Aftonbladet and Expressen portray the area of Järva and its continuing shootings. Using the critical discourse analysis method we read a total of 28 articles from the 1st of January to 31st of October 2021 to analyze.  In addition, we used Robert Entman’s framing theory with the aim to find out in which way the evening presses chose to frame and present the area itself and its shootings. Also applying Spivak’s othering theory, to find out if Aftonbladet and Expressen paint a scenario of “us and them” in their articles. The results clearly showed that the area of Järva is in a critical condition and is constructed as a war zone, suffering from shootings in the middle of the day in public places. Furthermore, the area itself is portrayed as if it does not belong to the normal society, it’s somehow “over there in the war zone”. Moreover, the criminals were described as brutal and reckless, as they shoot people to death in front of schools and grocery stores. The result also show that the evening press chose to use triggering words such as “the murder epidemic” and a “war zone” to describe how rough the situation is in the area of Järva. Key words: Järva, skjutningar, kritisk diskursanalys, vi och dem, gestaltningsteori.

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