京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第13294号 / 論農博第2877号 / 新制||農||1073(附属図書館) / 学位論文||R1||N5239(農学部図書室) / (主査)教授 清水 浩, 准教授 中嶋 洋, 教授 飯田 訓久 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

<p>Discrete element method (DEM) modeling is a common way to model particulate systems and processes. Since the number of particles in most pharmaceutical processes is incredibly large, modeling these substantial magnitudes of particles individually using DEM is not computationally reasonable. To simplify the DEM modeling, agglomerates or groups of particles are modeled instead. This change creates a disconnect between the real particle parameter values and the simulated particle parameter values. Thus, efficient and accurate calibration is needed for effective modeling. </p> <p>The methodology proposed in this thesis utilized a single commonly used bulk flowability measurement device, an annular shear cell, to calibrate for these DEM parameters with the help of dimensional analysis, design of experiments, and statistical tools. Three bulk responses were studied from the ring shear cell: the incipient yield internal friction angle, the critical state internal friction angle, and the bulk cohesion. The most important DEM parameters were isolated and subjected to a dimensional analysis to increase the generality of the results. A modified full-factorial study was then set up using the identified dimensionless parameters. The final calibration results were then validated using an independent flow through an orifice test using a Flodex^TM. </p> <p>This thesis demonstrates this proposed calibration methodology using three different powder samples, lactose, (hydroxypropyl) methyl cellulose (HPMC), and ABT-089. Using the DEM simulation results and the experimental measurements, predictive models were created for all three powder samples. For HPMC, the calibration errors were large while using spherical particles, so a non-spherical particle shape was introduced using the glued-sphere model in DEM. The calibration process was repeated with simulated non-spherical particles with an aspect ratio of two to create a new model for HPMC. </p> <p>The overall calibration procedure and the three models, when validated with the Flodex simulations and measurements, successfully predicted the Flodex results within one Flowability index range for all three powder samples. This demonstrates that this methodology can be used to successfully calibrate various DEM simulation parameters.</p>

This work deals with modeling the flow of particulate matter in rotary kilns. For this purpose, a combined CFD and Discrete Element Method (DEM) model was used. Using Ansys Fluent software, several simulations were performed in order to determine the mean residence time and movement of the material in the rotary drum dryer. Results of the computational model were used to develop a regression model of the mean residence time and compared to the values as given by empirical equations. Furthermore, a simplified sensitivity analysis was performed for the selected input parameters of the model such as the stiffness constant, air mass flow rate and the particle size.

In this study the breakage mechanics of brittle glass marbles was investigated. The pro-cess was to firstly investigate them in laboratory environment. The marbles or specimens was loaded until a crushing breakage occurred in a single point load test called Single Sphere Point load test in this document. From the test we could derive the crushing load, the deformation and strain, the tensile strength and other parameters needed for the second part of this work. Namely the numerical modelling, here we investigated the specimen with the Discrete Element method or DEM for shorts. The software used was an open sourced software created in MATLAB called DICE2D. Since the software was developed to only include the mathematical part of the numerical model several re-coding processes were needed, with other words the creation of add-ons to the software. The add-ons were automatic code created in Python where the user now are able to create a geometrical model for the specimen that the software can interpret. There were two add-ons created in order to generate a geometry, called the circumference method and the random generation method, i.e. different methods of creating a geometry. The first method, the circumference method creates circumferences filled with smaller particles with the same radii, then moves a step inward to the specimens center and fills another circumference until the center is reached. The second method, the random method generates particles positioned randomly inside the specimen with a random radii, created such that the radius of the particles is chosen with an interval, were the user can choose the smallest and the largest particle radius. It was found that both these add-ons were of great use with different purposes in mind. The circumference method was able to create a brittle material where the deformations were low. The random method also created a brittle material but since the particles were randomly positioned there also was empty space created such that the deformations were larger than the one found in the laboratory environment, since the empty space between the particles was closed before the plastic deformation could occur. Hence the second method of generation is more relevant for concrete and rock mechanics since in these cases this is the actual process, where the micro-cracks first closes then the elastic and plastic deformation occurs [Martin, 1993]. The first method, the circumference method is of great use when investigating the elastic deformations since here the particles are in contact. Thus creating the scenario for granular particles, In this thesis however the circumference method was used in order to create a solid specimen. For future use this add-on should be used in order such that each particle simulates an actual grain. The results found with both of these methods follows the results found in the laboratory test for the crushing load. But the incremental increase of force when the load is applied on the specimen was not able to be simulated. It is believed that the software is having difficulties to simulate brittle material due to the small deformations and the large loads.

Design step for Sigma-Delta ADC is introduced. Suitable solution for performance improvement of the original Sigma-Delta ADC, which meets new requirements on resolution of 16 bits and signal bandwidth 20-50 kHz is presented. Advantage of using multi-bit quantization and DEM DWA method reducing the linearity requirements of the internal feedback DAC is shown.

Conducting single frame orthorectification on satellite images to create an ortho-image requires four basic components, namely an image, a geometric sensor model, elevation data (for example a digital elevation model (DEM)) and ground control points (GCPs). For this study, orthorectification was executed numerous times (in three stages) and each time components were altered to test the geometric accuracy of the resulting ortho-image. Most notably, the distribution and number of ground control points, the quality of the elevation source and the geometric sensor model or lack thereof were altered. Results were analysed through triangulating and comparing the geolocation accuracy of the ortho-images. The application of these different methods to perform orthorectification encompass the aim of this paper, which was to investigate and compare the positional accuracies of ortho-images under various orthorectification scenarios and provide improved geometric accuracies of VHR satellite imagery when diverse ground control and elevation data sources are available. By investigating the influence that the distribution and number of GCPs and the quality of DEMs have on the positional accuracy of an ortho-image, it became clear that a reasonable increase in the number of uniformly distributed GCPs combined with progressively accurate DEMs will ultimately improve the quality of the orthorectified product. The results also showed that when more GCPs were applied, the smaller the difference in accuracy was between the different DEMs utilised. It was interesting to note that when it is suitable to manually collect well-distributed GCPs using a GPS handheld device over the study area then a very accurate result can be expected. Nonetheless, it is also important to note that if it is not possible/practical to achieve the latter, satellite based GCP collection do provide a very good alternative. It was also determined that utilising GCPs which were extracted from vector road layers to only cover specific areas in the image scene produced less favourable results. Several contributions towards improved orthorectification procedures were made in this study. These include the development of an automatic GCP extraction script (A-GCP-ES), written in the Python scripting language with the purpose to ease the process of manually placing GCPs on an input image when repeatedly performing orthorectification. / Thesis (PhD)--University of Pretoria, 2016. / Geography, Geoinformatics and Meteorology / PhD / Unrestricted

The objective of the thesis is to design a new detection method of terrain skeleton lines from airborne laser scanning data. The theoretical part provides a brief introduction to airborne laser scanning issue. There are presented major principles of the technology and procedures applied to create digital terrain model from laser data. There is also described an application of airborne laser scanning in the area of the Czech Republic in detail and follows an exact specification of key terms of the thesis. From the geomorphology, topography and geoinformatics point of view there are defined especially terms like terrain skeleton lines, breakline, valley and ridge. Literary research consists of the summary of already published method of breakline detection. There are algorithms focused on data processing in form of original point cloud as well as algorithms focused on processing data in the raster form. Primary goal of the theoretical part is to express major principles of already published method of detection. The practical part firstly introduces data that are used further in the thesis. The objective of the thesis is a description of a new method of detection of terrain skeleton lines. The method processes laser data converted into raster form and it is based on the analysis of transverse elevation profile...

This study examines how one of the most influential Swedish newspapers, Aftonbladet,reports about the suburb Rosengård. Rosengård is located in Malmö and have become asymbol of Sweden’s suburbs and immigration policy. Both national and internationalmedia have reported about organized crime, shootings and different social problems inRosengård. The area is considered to be a particularly vulnerable area. At the sametime, many researchers believe that the media reporting regarding suburbs does notnecessarily correspond to the reality. The methods used in this study are a quantitativeand qualitative content analysis. The material studied are news articles concerningRosengård that were published in Aftonbladet in the last five years. The purpose was to,based on Goffman’s framing theory, investigate how Aftonbladet frames Rosengård andthe people who lives there. The purpose was also to investigate whether Aftonbladet,based on Hall’s and Said’s theories of representation and orientalism, creates an “us andthem”-perspective. The results show that Rosengård is portrayed as a criminal andproblematic area. As in previous research about media and suburbs, the results of thisstudy show that Rosengård is presented as a different and deviant area in comparison tothe “ordinary society”. It is rarely people living in the area who are quoted, referencedor described in the articles. Instead, it is often the police or government officials whogets to describe the situation in Rosengård. In cases where the residents in the area areallowed to speak, or are described, it is often based on their role as immigrants. The factthat these articles emphasize that the residents are immigrants but have made a careerand are against crime, we believe that Aftonbladet creates an us-and-them-perspective.This is based on that Aftonbladet portrays the residents as exceptional cases to “theordinary immigrant”. The consequences of Aftonbladet frames could be that the societygets an idea of the area that does not have to agree with the reality and that Rosengårdbecomes even more segregated.

The Arab Spring put several revolutions in motion in the Middle East and North Africa. However, Tunisia was the only country that succeeded with a democratization process, making the country a fairly new democracy. Simultaneously, independent research networks and organizations whose main focus is democracy and democratic values such as Freedom House, V-Demand the Arab Barometer are presenting worrying information about democracy around the world. Democracy is in crises - evident by the remarkable decline or erosion in democratic norms and practices. While scholars have already begun investigating the causes of democratic deconsolidation or backsliding in the context of western democracies, notably those of western Europe and the US, still little is known with regards to new democracies from other parts of the globe. To fill this research gap, this qualitative case study focuses on Tunisia, with the core objective to investigate whether or not Tunisia is experiencing democratic deconsolidation. By using the three criteria described by the political scientist Yascha Mounk in his deconsolidation theory, the result suggests that while democratic values are still quite strong amongst the Tunisian citizens, it is evident that a majority of the Tunisian citizens are experiencing institutional dissatisfaction and low institutional trust.

Die Distinkte-Element-Methode (Programm UDEC von Itasca) wurde angewendet, um das Bruch- und Verformungsverhalten von geklüfteten Gebirgsbereichen beim Tunnelbau und die Interaktionen zwischen Gebirge und Tunnelausbau systematisch zu untersuchen. Durch die numerischen Untersuchungen wurden die Einflussfaktoren auf das Bruch- und Verformungsverhalten und die Hauptversagensarten von geklüftetem Fels aufgezeigt. Ein neues „De- und Reaktivierungsverfahren“ wurde entwickelt und erfolgreich verwendet. Beruhend auf der Simulation der Anker- und Spritzbetonsicherungen und der einzelnen Bauzustände bei Teilausbrüchen wurde ein Konzept zur Beurteilung der Standsicherheit eines Hohlraums in geklüftetem Fels und zur Dimensionierung der Sicherungsmaßnahmen dargestellt.