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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Understanding state-of-the-art material classification through deep visualization

Donovan, Jordan 13 December 2019 (has links)
Neural networks (NNs) excel at solving several complex, non-linear problems in the area of supervised learning. A prominent application of these networks is image classification. Numerous improvements over the last few decades have improved the capability of these image classifiers. However, neural networks are still a black-box for solving image classification and other sophisticated tasks. A number of experiments conducted look into exactly how neural networks solve these complex problems. This paper dismantles the neural network solution, incorporating convolution layers, of a specific material classifier. Several techniques are utilized to investigate the solution to this problem. These techniques look at specifically which pixels contribute to the decision made by the NN as well as a look at each neuron’s contribution to the decision. The purpose of this investigation is to understand the decision-making process of the NN and to use this knowledge to suggest improvements to the material classification algorithm.
22

Center for Making Material and Craftsmanship: A dialog between the crafted and the fabricated

Petersen, William G. Jr. 14 August 2008 (has links)
This thesis is a personal exploration about the making of architecture, not just through the exploration of a particular idea, but as a synthesis of many ideas within the imagination of the architect. Beyond the investigations of space, shadow, light, building, drawing, and contemplation of what Architecture is and can be, there exists the underlying effort to create a personal architecture that reflects the values and ideas of the person who created it. The aim was to create Architecture that has a meaningful depth to it beyond the façade and that reflects both a sense of poetics and pragmatism. But within that experience was an attempt to investigate the realm that exists between the poetic and the pragmatic, the creating of that in-between realm through materiality that reflects the poetics of pragmatism. In the end that exploration came through the process of exploring the idea of the hand-made and the fabricated. In essence, this thesis presents a dialogue between the hand-made (poetic) material and the fabricated (pragmatic) material as an expression of the Architecture. / Master of Architecture
23

Composition, properties and surface structure of tribochemically deposited coatings / Sammansättning, egenskaper och ytstruktur hos tribokemiskt deponerade beläggningar

Åkerlund, Eva-Brita January 2011 (has links)
Five tribochemically deposited coatings on honed cast iron cylinder liner segments has been studied with respect to surface properties, material composition, coating thickness, hardness and friction. Methods like Light Optical Microscopy (LOM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), 3D topography using white light interferometry (VSI) and Electron Spectroscopy for Chemical Analysis (ESCA) were used to study the surface, coating thickness and material composition. Lubrication regimes (friction) were studied using a test set-up in a Lathe. An in-situ scratcher and nano indenter were used to study the hardness. It was found that the honing plateau surface is smoothened by the coating process while the honing scratches are kept more or less intact. The deposited coating thickness is approximately 10-100 nm. The coating is softer than the substrate and shows a butter-like behavior when scratched. Using only sulfur additive in the process fluid gives a smooth surface and an evenly distributed coating. Tungsten additive in the process fluid gives a thicker coating but a more irregular material distribution. Tungsten additive in the process fluid does not seem to stimulate the formation of WS2, but rather WO3 is formed.
24

Ab initio study of transition metal carbides and actinide compounds

Sun, Weiwei January 2015 (has links)
Two classes of materials are investigated using ab intio methods based on density functional theory. The structural properties, electronic structure and thermodynamic properties of binary and ternary transition metal carbides are discussed in details. In addition, two actinide compounds will be presented. A new actinide monoxide, ThO, is predicted to be stable under pressure, and the weakly correlated UN is investigated as regards to its magnetic properties and electronic structure. The atomic and electronic structures of various types of single defects in TiC such as vacancies, interstitial defects, and antisite defects are investigated systematically. Both the C-poor and C-rich off-stoichiometric Ti1-cCc composition (0.49≤c≤0.51) have been studied. For the electronic structure, the difference of density of states (dDOS) is introduced to characterize the changes produced by the defects. Concerning the atomic structures, both interstitial defects and antisites are shown to induce the formation of C dumbbells or Ti dumbbells. To date, the Ti self-diffusion mechanism in TiC has not been fully understood, and particularly the Ti diffusion is much less studied in comparison with the C diffusion. Therefore, the self-diffusion of Ti in sub-stoichiometric TiC is studied, and the formation energies, migration barriers for Ti interstitials, dumbbells and dumbbell-vacancy clusters are reported. Some of the calculated activation energies are close to the experimental values, and the migration of Ti dumbbell terminated by C vacancies gives the lowest activation energy, which is in good agreement with the experimental data. These studies must be continued to obtain a full description (including phonon contributions, prefactors, etc.) of all the feasible diffusion mechanisms in TiC. The focus is then shifted from the light transition metal carbides to the heavy transition metal carbides. Various structures of Ru2C under ambient conditions are explored by using an unbiased swarm structure searching algorithm. The structures with R3m (one formula unit) and R-3m symmetry (two formula units) have been found to be lower in energy than the P-3m1 structure, and also to be dynamically stable at ambient conditions. The R-3m structure is characterized by emergence of the Ru-Ru metallic bonding, which has a crucial role in diminishing the hardness of this material. The study of correlation and relativistic effects in Ta2AlC is also presented. We have shown that going from a scalar relativity to a fully relativistic description does not have a significant effect on the computed electronic and mechanical properties of Ta2AlC. In addition, the calculations show that the structural and mechanical properties of Ta2AlC are strongly dependent on other details of theoretical treatment, such as the value of the Hubbard U parameter. The comparison between our results and experimental data point to that Ta2AlC is a weakly correlated system, which originates from that the 5d band is relatively wide in comparison with that of the 3d band. The existence of a rock salt Thorium monoxide (ThO) under high pressure is theoretically predicted. A chemical reaction between Th and ThO2 can produce a novel compound thorium monoxide under sufficient external pressure. To determine the pressure range where this reaction can be observed, we have identified two extreme boundaries by means of different theoretical approaches. The first one is given by a fully relativity DFT code in local density approximation (LDA). The second one is given by a scalar relativistic DFT code in generalized gradient approximation (GGA). It is found that ThO is energetically favored between 14 and 26 GPa. The f orbitals are filled at the expense of s and d electrons states of Th metal, under the action of pressure. The d-p hybridization leads to the stability of metallic ThO. Dynamical stability is also investigated by computing the phonon dispersions for the considered structures at high pressure. The electronic structure and magnetic properties of a promising nuclear fuel material, uranium mononitride (UN), are studied by means of density functional theory (DFT) and several extensions, such as dynamical mean-field theory (DMFT), disordered local moment (DLM) approach, and the GW method. The role of the relativistic corrections is analyzed for different levels of approximation. The importance of correlation effects is assessed through a detailed comparison between calculated electronic structure and measured photoemission spectrum, which helps to clarify the dual itinerant/localized nature of the 5f states of U in UN. Important effects are also observed for the 2p states of nitrogen, which are positioned at much lower energies that are difficult to be well treated in the conventional electronic structure calculations. / <p>QC 20141219</p>
25

Konkret material i matematikundervisningen

Englund, Ida January 2016 (has links)
En av skolverkets kvalitetsgranskningar visade att många elever hade negativa erfarenheter av ämnet matematik och den undervisning som de har fått i ämnet. En annan undersökning visar att lärarna och matematikundervisningen är alltför styrd av läroböcker. En förändring av arbetssätt i ämnet matematik behöver ske enligt skolverket. Ett sätt kan vara att arbeta med konkret material för att få en mer varierad undervisning.Detta examensarbete lyfter fram fem lärares uppfattningar om, erfarenheter kring och användning av konkret material i matematikundervisningen. Detta undersöks genom kvalitativa observationer och intervjuer. Resultatet i studien visar att samtliga informanter tycker att elevernas motivation och förståelse ökar markant genom att arbeta med konkret material. De berörda lärarna arbetar med konkret material i matematiken dagligen och gärna vid genomgångar. De tillfrågade lärarna ser många fördelar med materialet medan nackdelar är svårare att se.
26

A Material Flow Evaluation at Scania Production Slupsk S.P.S

Gustafsson, Daniel, Johansson, Mikael January 2007 (has links)
This master’s thesis is performed at Department of Management and Engineering Linköping University, for Scania Omni at Scania Production Slupsk (S.P.S). Omni is responsible for development, manufacturing and marketing of city, suburban and intercity buses. After acquisition of the production unit in Slupsk in 2002 lower production cost per bus is possible. But without control over the organisation costs are rising due to late delivery fees and high stock levels. At the outset, the thesis included three clearly defined objectives: - Map the present situation at Scania Production Slupsk regarding material flow from supplier to assembly line including a part and storage analysis. - Benchmark the current routines at Scania Production Slupsk with other successful companies. Furthermore, conduct literature research in order to find theories and philosophies that support problem analysis and thesis solution. - Develop standard routines for material control methods (MCM) and material supply methods (MSM). A complimentary objective is to work as a catalyst during the time of the thesis. The mapping of the present situation showed that MCM and MSM are very tight connected to each other. It was questioned whether this structure was the best way to manage the material flow. After a parts and storage analysis, material was divided into different segments depending of price, consumption and movement. The benchmarking studies showed different ways to manage the material flow. Implementation of unit load, kanban and clear defined interface between departments showed potential to improve the material handling and increase effectiveness. New routines and part segment definitions described in a logistics manual (Appendix I) were made align with a comparison between previous and recommended definitions. The result showed that some parts needs to be controlled differently. Primary recommendations are that logistics manual shall be used when new parts are introduced into the Scala system. Responsible personnel are suppose to give suggestion concerning decision making of MCM and MSM and with help of the logistics manual the work can be more efficient, resulting in a material flow that is flexible and have potential for improvements. Secondary, to avoid material handling to some extent implementation of two-bin system is recommended. Additional recommendations regarding two-bin system is to handle material according to unit load, which enable FIFO, traceability and higher turn over rate
27

Matematiska arbetsmetoder / How six pedagogues in third and fourth grade teaches mathematics and which methods they use

Zengin, Nazli January 2010 (has links)
The purpose of this study is to give a description of how six pedagogues in the third and fourth grade teaches mathematics and which working methods they use. When using the term working methods it is implied that it can for example be outdoors pedagogic, laboratory material, problem solutions et cetera. This material can both be an everyday material or a pedagogical material. The research was carried through by interviews and observations. Six pedagogues were interviewed in two different districts. Most of the pedagogues taught in the third grade and some in the fourth grade. The results show that all of the pedagogues use outdoor pedagogic, laboratory material and the schoolbook when teaching in mathematics.   According to the pedagogues elaborative material is when the pupils use their hands and bodies. The pupils are supposed to feel and act. The pedagogues work with elaborative material first by giving an introduction about the material that they are going to use in the mathematical lessons. The pedagogues use elaborative material so that the pupils get a better understanding. The pedagogues also considered that using elaborative material contributed to the pupils learning by several other senses, which then led to an easier and more fun understanding of mathematics.
28

A Material Flow Evaluation at Scania Production Slupsk S.P.S

Gustafsson, Daniel, Johansson, Mikael January 2007 (has links)
<p>This master’s thesis is performed at Department of Management and Engineering Linköping University, for Scania Omni at Scania Production Slupsk (S.P.S). Omni is responsible for development, manufacturing and marketing of city, suburban and intercity buses. After acquisition of the production unit in Slupsk in 2002 lower production cost per bus is possible. But without control over the organisation costs are rising due to late delivery fees and high stock levels. At the outset, the thesis included three clearly defined objectives:</p><p>- Map the present situation at Scania Production Slupsk regarding material flow from supplier to assembly line including a part and storage analysis.</p><p>- Benchmark the current routines at Scania Production Slupsk with other successful companies. Furthermore, conduct literature research in order to find theories and philosophies that support problem analysis and thesis solution.</p><p>- Develop standard routines for material control methods (MCM) and material supply methods (MSM).</p><p>A complimentary objective is to work as a catalyst during the time of the thesis.</p><p>The mapping of the present situation showed that MCM and MSM are very tight connected to each other. It was questioned whether this structure was the best way to manage the material flow. After a parts and storage analysis, material was divided into different segments depending of price, consumption and movement. </p><p>The benchmarking studies showed different ways to manage the material flow. Implementation of unit load, kanban and clear defined interface between departments showed potential to improve the material handling and increase effectiveness.</p><p>New routines and part segment definitions described in a logistics manual (Appendix I) were made align with a comparison between previous and recommended definitions.</p><p>The result showed that some parts needs to be controlled differently. Primary recommendations are that logistics manual shall be used when new parts are introduced into the Scala system. Responsible personnel are suppose to give suggestion concerning decision making of MCM and MSM and with help of the logistics manual the work can be more efficient, resulting in a material flow that is flexible and have potential for improvements.</p><p>Secondary, to avoid material handling to some extent implementation of two-bin system is recommended. Additional recommendations regarding two-bin system is to handle material according to unit load, which enable FIFO, traceability and higher turn over rate</p>
29

MATERIAL, - vad, hur och varför? : - En undersökning om material i bildundervisningen.

Andersson, Isabelle January 2013 (has links)
No description available.
30

Die Sprache der Materialien : Anleitung zu einer Ikonologie der Werkstoffe /

Raff, Thomas. January 2008 (has links)
Zugl.: Augsburg, Universiẗat, Habil.-Schr., 1991.

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