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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.
131

Topological (Bio)Timber: An Algorithm and Data Approach to 3d Printing a Bioplastic and Wood Architecture

Macias, Diego 29 September 2017 (has links)
No description available.
132

Properties of 3D Printed Continuous Fiber-Reinforced CNTs and Graphene Filled Nylon 6 Nanocomposites

Liu, Zhihui January 2017 (has links)
No description available.
133

The Development of 3D Printable Materials

Bootsma, Katherine Jean 02 December 2016 (has links)
No description available.
134

Cellulose and polypropylene filament for 3D printing / Cellulosa och polypropen filament för 3D-utskrivning

Kwan, Isabella January 2016 (has links)
Additive manufacturing has become a very popular and well mentioned technique in recent years. The technique, where 3 dimensional (3D) printing is included, creates opportunities to develop new designs and processing systems. As a research institute within the forest based processes and products, Innventia AB has an idea of combining 3D printing with cellulose. The addition of cellulose will increase the proportion of renewable raw material contributing to more sustainable products. However, when cellulose is added the composition of the filaments changes. The main aim for the project is to devise methodologies to improve properties of composite filaments used for 3D printing. Filament in 3D printing refers to a thread-like object made of different materials, such as PLA and ABS, that is used for printing processes. A literature study was combined with an extensive experimental study including extrusion, 3D printing and a new technique that was tested including 3D scanning for comparing the printed models with each other. The extruding material consisted of polypropylene and cellulose at different ratios, and filaments were produced for 3D printing. The important parameters for extruding the material in question was recorded. Because the commingled material (PPC) was in limited amount, UPM Formi granulates, consisting of the same substances, was used first in both the extrusion and printing process. Pure polypropylene filaments were also created in order to strengthen the fact that polypropylene is dimensional unstable and by the addition of cellulose, the dimensional instability will decrease. After producing filaments, simple 3D models were designed and printed using a 3D printing machine from Ultimaker. Before starting to print, the 3D model needed to be translated into layer-by-layer data with a software named Cura. Many parameters were vital during printing with pure polypropylene, UPM and PPC. These parameters were varied during the attempts and marked down for later studies. With the new technique, in which 3D scanning was included, the 3D printed models were compared with the original model in Cura in order to overlook the deformation and shape difference. The 3D scanner used was from Matter and Form. Photographs of the printed models, results from the 3D scanner, and screenshots on the model in Cura were meshed together, in different angles, using a free application named PicsArt. The result and conclusion obtained from all three parts of the experimental study was that polypropylene’s dimensional stability was improved after the addition of cellulose, and the 3D printed models’ deformation greatly decreased. However, the brittleness increased with the increased ratio of cellulose in the filaments and 3D models. / Additiv tillverkning har på den senare tiden blivit en mycket populär och omtalad teknik. Tekniken, där tredimensionell (3D) utskrivning ingår, ger möjligheter att skapa ny design och framställningstekniker. Som ett forskningsinstitut inom massa- och pappersindustrin har Innventia AB en ny idé om att kombinera 3D-utskrivning med cellulosa. Detta för att höja andelen förnybar råvara som leder till mer hållbara produkter. Dock kommer filamentens sammansättning vid tillsättning av cellulosa att ändras. Det främsta syftet med detta projekt är att hitta metoder för att förbättra egenskaperna hos de kompositfilament som används för 3D-utskrifter. Filament inom 3D-utskrivning är det trådlika objektet gjort av olika material, såsom PLA och ABS, som används vid utskrivningsprocessen. En enkel litteraturstudie kombinerades med en experimentell studie. Det experimentella arbetet var i fokus i detta projekt som omfattade extrudering, 3D-utskrivning samt en ny teknik som prövades, där 3D-scanning ingick, för att jämföra de utskrivna modellerna med varandra. Extruderingsmaterialet bestod av polypropen och cellulosa av olika halter, och av detta material tillverkades filament för 3D-utskrivning. De viktiga parametrarna för extrudering med det önskade materialet antecknades. Eftersom mängden cominglat material (PPC) var begränsat, användes först UPM Formi granuler, som består av samma substanser som i PPC, i både extruderingen och utskrivningen. Filament av ren polypropen tillverkades också för att stärka det faktum att polypropen är dimensionellt instabil. Genom att tillsätta cellulosa minskades dimensionsinstabiliteten. Efter att filamenten hade tillverkats, designades enkla 3D-modeller för utskrivning med en 3D-utskrivare från Ultimaker. Innan utskrivningen kunde börja behövde 3D-modellen bli översatt till lager-på-lager-data med hjälp av en programvara vid namn Cura. Många parametrar är viktiga vid utskrivning med ren polypropen, UPM samt PPC. Temperatur och hastighet varierades för de olika försöken och antecknades för senare studier.Med den nya tekniken, där 3D-scanning ingår, jämfördes de utskrivna 3D-modellerna med originalmodellen i Cura för att se över deformationen och formskillnaden. Den 3D-scanner som användes kom från Matter and Form. Fotografier på de utskrivna modellerna, resultaten från 3D-scannern och bilder på modellerna i Cura sammanfogades i olika vinklar med hjälp av ett gratisprogram som heter PicsArt. Det resultat som erhölls och den slutsats som kunde dras utifrån alla tre delarna av den experimentella studien var att polypropens dimensionsinstabilitet minskades efter tillsatsen av cellulosa, och att de 3D-utskrivna modellernas deformation minskade kraftigt. Skörheten ökade ju högre halt cellulosa som filamenten och de utskrivna modellerna innehöll.
135

Innovativ kostnadsberäkningsmodell för additiv tillverkning : En kvalitativ fallstudie med bidrag till utvecklingen av självkostnadsberäkning

Eriksson, Martin, Johansson, Filip, Nilsson-Öst, Jonas January 2022 (has links)
Actors within the manufacturing industry are constantly looking for innovative manufacturing methods to remain competitive. Additive manufacturing (AM), also referred to as 3D printing, is considered to have a good potential in the development towards industry 4.0. Though the cost control of AM-processes is an important step towards future business opportunities, little research has been implemented about how to design a cost calculation model for AM technology since it has not been industrialized to a significant extent. The purpose of this study is to develop an AM cost calculation model for the metal industry. The study is conducted through a qualitative case study at Seco Tools AB, a Swedish manufacturing company that carries out research and production operations of AM technology. By using literature review, data collection on the AM process, interviews with staff at the case company, a new AM cost calculation model is formulated specifically for the AM process at the case company. The proposed model is quantitatively and qualitatively validated with a set of real data from the case company and the satisfied result is obtained. The theoretical contribution of this study is the knowledge of what influencing factors should be included, what uncertainties exist and how corresponding adjustments should be made in a cost calculation model for AM. The practical contribution is the development of an innovative, user-friendly and generalizable cost model without user competence requirements within AM. Compared to the earlier models, the developed model is easier to apply when calculating the costs of a complex process. The model can be used as a basis for decision making in budgeting, scenario analysis, determination of occupancy rate or cost calculation of individual build jobs. / Aktörer inom tillverkningsindustrin letar ständigt efter innovativa tillverkningsmetoder för att förbli konkurrenskraftiga. Additiv tillverkning (AM), även kallad 3D-printing, anses ha en god potential i utvecklingen mot industri 4.0. Även fast kostnadskontroll av AM-processer är ett viktigt steg mot framtida affärsmöjligheter, har lite forskning genomförts om hur man kan designa en kostnadsberäkningsmodell för AM-teknik eftersom den inte har industrialiserats i betydande utsträckning. Syftet med denna studie är att utveckla en kostnadsberäkningsmodell för AM inom metallindustrin. Studien genomförs genom en kvalitativ fallstudie på Seco Tools AB, ett svenskt tillverkningsföretag som bedriver forskning och produktionsverksamhet inom AM-teknik. Genom att använda litteraturinsamling, datainsamling om AM-processen samt intervjuer med personal på fallföretaget formas en ny kostnadsberäkningsmodell för AM specifikt mot AM-processen vid fallföretaget. Den föreslagna modellen är kvantitativt och kvalitativt validerad med en uppsättning verkliga data från fallföretaget och ett tillfredsställande resultat erhålls. Det teoretiska bidraget för denna studie är kunskapen om vilka påverkande faktorer som bör ingå, vilka osäkerheter som återfinns och hur motsvarande justeringar bör göras i en kostnadsberäkningsmodell för AM. Det praktiska bidraget är utvecklandet en innovativ, användarvänlig och generaliserbar kostnadsmodell utan kompetenskrav inom AM. Jämfört med tidigare modeller är den utvecklade modellen lättare att tillämpa vid beräkning av kostnader i en komplex process. Modellen kan användas som underlag för beslutsfattande vid budgetering, scenarioanalys, bestämning av beläggningsgrad eller kostnadsberäkning av enskilda byggjobb.
136

Development of in-situ flow electrochemical Scanning Transmission X-ray Microscopy

Prabu, Vinod January 2017 (has links)
Understanding electrically activated processes at electrode-electrolyte interfaces is needed to improve many technologies, including energy conversion, semiconductor devices, bio-sensors, corrosion protection, etc. In-situ spectro-electrochemical studies based on a wide range of spectroscopies are particularly useful. Scanning Transmission X-ray microscopy (STXM) is a synchrotron-based technique which measures near-edge X-ray absorption fine structure (NEXAFS) with high spatial resolution. In addition to information on morphology, STXM also provides chemical state analysis using the X-ray absorption data, which makes in-situ STXM studies of electrochemical process of special interest. This thesis reports ex-situ and in-situ STXM based qualitative and quantitative studies on copper (Cu) electrodeposition and electrostripping. The influence of electrolyte pH on the distribution of Cu(I) and Cu(0) species electrodeposited from aqueous CuSO4 solutions was studied. An instrument capable of performing in-situ flow electrochemical STXM studies was designed and fabricated. The performance of this device was evaluated for in-situ Cu electrodeposition studies. Findings based on ex-situ and in-situ STXM studies are discussed. Suggestions are made for further instrumentation improvements. / Thesis / Master of Science (MSc)
137

Analysis of Additively Manufactured 17-4PH Stainless Steel

Coulson, Simon January 2018 (has links)
Selective laser melting of nitrogen gas atomized 17-4PH stainless results in up to 50% lower yield strength and 600% higher elongation compared to traditionally processed, wrought 17-4PH. This drastic difference in mechanical properties is commonly attributed to the presence of high volume fractions of retained austenite within the as-built microstructure. The factors leading to the increased level of retained austenite have not been clarified in the literature. Furthermore, the amount of retained austenite reported within published literature vary widely, even with the use of identical process parameters. Manufacturers of selective laser melting systems state that solution annealing and precipitation hardening will achieve traditional mechanical properties, thereby removing all retained austenite. Once again, it is not clear, how the recommended solution and precipitation treatments lead to the desired changes in microstructure. The research within this thesis establishes that there is up to 0.12wt% higher nitrogen content within additively manufactured 17-4PH, compared to traditionally manufactured 17-4PH, as a result of the powder atomization process. The increased nitrogen is able to stabilize the austenitic phase by reducing the Ms temperature below ambient temperatures. Fertiscope bulk phase analysis demonstrates that the processing atmosphere during selective laser melting cannot alter the fraction of retained austenite in the as-built material. The depression of the Ms temperature in the printed parts is confirmed by dilatometry. Due to the TRIP phenomenon, during sample preparation, it was found that the austenite would transform to 80% martensite at the surface. This transformation will greatly impact the phases detected when x-ray diffraction is used for analysis, leading to a wide variety of reported retained austenite values within literature. A mechanism based on the precipitation of nitrides during solution-treatment has been proposed to explain how heat-treatment of the printed parts can lead to a martensitic microstructure with comparable mechanical properties to those of wrought alloys. / Thesis / Master of Applied Science (MASc) / 17-4PH stainless steel is a martensitic alloy, that can be precipitation hardened when used in traditional manufacturing processes. Within a selective laser melting process, it will exhibit up to 50% lower yield strength and 600% higher elongation. This behaviour is caused by retained austenite, which is stabilized by the introduction of nitrogen during the powder atomization process. As a result, the alloy exhibits transformation induced plasticity. Existing literature states the alloy’s microstructure can be controlled by altering the selective laser melting process atmosphere or using heat treatment to achieve traditional mechanical properties. However, the production and preparation of samples generates a surface transformation which was misinterpreted as a complete bulk transformation. Therefore, the change in microstructure from altering the process atmosphere is only detectable through surface analytical techniques. It is proposed that the rapid cooling rates of SLM form a non-equilibrium state, keeping nitrogen in solution. Subsequent heat treatment allows the formation of nitrides resulting in the Ms being brought above room temperature.
138

Fabrication and Characterization of Lithium-ion Battery Electrode Filaments Used for Fused Deposition Modeling 3D Printing

Kindomba, Eli 08 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Lithium-Ion Batteries (Li-ion batteries or LIBs) have been extensively used in a wide variety of industrial applications and consumer electronics. Additive Manufacturing (AM) or 3D printing (3DP) techniques have evolved to allow the fabrication of complex structures of various compositions in a wide range of applications. The objective of the thesis is to investigate the application of 3DP to fabricate a LIB, using a modified process from the literature [1]. The ultimate goal is to improve the electrochemical performances of LIBs while maintaining design flexibility with a 3D printed 3D architecture. In this research, both the cathode and anode in the form of specifically formulated slurry were extruded into filaments using a high-temperature pellet-based extruder. Specifically, filament composites made of graphite and Polylactic Acid (PLA) were fabricated and tested to produce anodes. Investigations on two other types of PLA-based filament composites respectively made of Lithium Manganese Oxide (LMO) and Lithium Nickel Manganese Cobalt Oxide (NMC) were also conducted to produce cathodes. Several filaments with various materials ratios were formulated in order to optimize printability and battery capacities. Finally, flat battery electrode disks similar to conventional electrodes were fabricated using the fused deposition modeling (FDM) process and assembled in half-cells and full cells. Finally, the electrochemical properties of half cells and full cells were characterized. Additionally, in parallel to the experiment, a 1-D finite element (FE) model was developed to understand the electrochemical performance of the anode half-cells made of graphite. Moreover, a simplified machine learning (ML) model through the Gaussian Process Regression was used to predict the voltage of a certain half-cell based on input parameters such as charge and discharge capacity. The results of this research showed that 3D printing technology is capable to fabricate LIBs. For the 3D printed LIB, cells have improved electrochemical properties by increasing the material content of active materials (i.e., graphite, LMO, and NMC) within the PLA matrix, along with incorporating a plasticizer material. The FE model of graphite anode showed a similar trend of discharge curve as the experiment. Finally, the ML model demonstrated a reasonably good prediction of charge and discharge voltages.
139

Habitat on Mars

Hadkar, Aditi Anil 31 May 2024 (has links)
The information contained in this thesis explores ways to develop a habitat for human settlement on Mars. Currently, most designs for living on Mars focus primarily on survival and emphasize the technological aspects necessary for sustaining life. However, there is a lack of holistic consideration for what life on Mars would entail beyond mere survival. These existing designs are understandably geared towards astronauts who will spend only a few months on Mars. In contrast, this project is dedicated to envisioning the future of Mars settlement, aiming to support astronauts who intend to permanently live and establish communities on Mars, ultimately transforming them into Martians. The project adopts a human-centric approach by integrating biophilic design principles to enhance the well-being of future Martian inhabitants. It seeks to address potential psychological challenges that settlers on Mars may encounter, offering innovative solutions rooted in biophilia. This approach aims to create environments that foster connection with nature, promote mental health, and support overall quality of life for individuals living on Mars. Humans have evolved over millions of years to thrive on Earth, and many of our primal instincts are deeply rooted in our hunter-gatherer ancestry. Transitioning humans to live on another planet would uproot them from their natural environment, potentially depriving them of these primal instincts and causing psychological challenges. (Szocik, n.d.) This project aims to address these issues through architectural solutions. By designing habitats that consider and accommodate our innate instincts and connections to nature, we can mitigate the psychological impacts of living on a different planet. The goal is to create environments on Mars that resonate with our evolutionary heritage, fostering psychological well-being and adaptation in extra-terrestrial settlements. / Master of Architecture / This thesis looks at how to create a habitat for humans to live on Mars. Right now, most designs focus mainly on survival and the technology needed to sustain life. Most don't really consider what everyday life would be like beyond just staying alive. Most current designs are for astronauts who will only be on Mars for a few months. This project, however, imagines a future where people live on Mars permanently and form communities, essentially becoming Martians. The project uses a design method that focuses on human needs at a subconscious and psychological level. It incorporates biophilic design principles, which emphasize our connection to nature, to improve the well-being of future Martian inhabitants. This approach aims to address psychological challenges that settlers on Mars might face, offering innovative solutions based on biophilia. The goal is to create environments that foster a connection with nature, promote mental health, and support a good quality of life. Humans have evolved over millions of years to live on Earth, and many of our basic instincts are tied to our hunter-gatherer ancestors. Moving to another planet could take us away from our natural environment and cause psychological challenges. This project aims to tackle these issues through thoughtful architectural design. By creating habitats that consider our natural instincts and connections to nature, we can reduce the psychological impacts of living on Mars. The goal is to design environments that align with our evolutionary background, helping people adapt and thrive in extra-terrestrial settlements.
140

Moon base: ad lunam

Voelcker, Ana Carolina January 2023 (has links)
The Moon is the closest celestial body to us. It is also the one we know most about, the only one we have visited so far, and our constant companion. With NASA's new Artemis program and newfound interest in exploring the Moon and beyond, my proposal is to create a base on the Moon for further space exploration, scientific development and establishment of an extraterrestrial colony. Dealing with obstacles such as lack of resources, radiation and no atmosphere, my project combines different constructive strategies, such as 3D-printing, excavating and inflatable membranes, to create an environment where humans can live and thrive on the Moon. The habitat allows for performing experiments and engaging in the basic survival activities, but also creates a home in such a challenging and distant place. Creating varied layers of habitability and protection ensure for a productive and entertaining existence on our one and only satellite, paving way to further explore the Solar System.

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