Дисертації: "Printing forms"

1

Palazzolo, Robert D. (Robert David) 1973. "Formulation of oral dosage forms by three dimensional printing." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50617.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.
Includes bibliographical references (p. 93).
Pharmaceutical grade materials were used in the fabrication of fast-release and extended-release oral dosage forms. Tablets were processed by employing a method of solid freeform fabrication known as three dimensional printingTM (3DPTM). A microcrystalline cellulose powder was used in combination with pH-dependent and permeable polymeric binder solutions. Release studies in acidic media were performed using both dye and drug (antihistamine) as actives. Deposition was performed by micro pipette into concept devices. It was concluded that printing parameters could be used to control the microstructure and release behavior. The performance of a drop-on-demand inkjet printing system was evaluated to be highly accurate, and the system was used in the fabrication of model oral dosage forms. Tablets were constructed with a permeable polymer as binder. Mechanical tests showed that the tablets were comparable to industry references for both strength and friability. A USP dissolution method involving an acid and buffer stage was used for extended-release studies. Release by diffusion was found to depend on device porosity level and drug distribution as defined during fabrication.
by Robert D. Palazzolo.
S.M.

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2

Kyobula, Mary. "Manufacturing of oral solid dosage forms using 3D inkjet printing." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42980/.

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Ink-jet printing is a precise and versatile technique that accurately deposits small volumes of solutions (pico litres) in specific locations. Recently inkjet printing has attracted increasing attention in the pharmaceutical industry because of its ability to deliver low adjustable doses, variable drug release profiles and drug combinations suitable for the paradigm of personalised medicines. The significant growth in the aging population and the rise in the number of patients suffering from multiple chronic diseases are the key drivers. The current traditional tablet compression methods are largely limited in terms of flexibility and complexity of dosage form. There is a need for new innovative technologies that can produce bespoke medicines in a relatively cheap and efficient manner at the point of care. 3D inkjet printing (3DIJP) provides a platform with the potential to address the above need. This thesis investigates the capability of 3DIJP as a tool for manufacturing solid dosage forms. In chapter 3, a piezoelectric drop on demand printer was used. The chapter focuses on two solvent based inkjet printing methods. In the first solvent based method, excipients including hydroxypropyl methylcellulose (HPMC), poly (vinyl pyrrolidone) (PVP) and Eudragit RL were investigated for printability. PVP (K10) which showed the best printability behaviour was loaded with digoxin or carbamazepine (CBZ) and printed to obtain films. In the second solvent based method, a solution containing CBZ dissolved in a mixture of of polyethylene glycol diacrylate (PEGDA) and with poly(caprolactone dimethyl acrylate) (PCLDMA) was printed and polymerised in situ using ultraviolet light to form films. The printed drug loaded films were investigated using time of flight secondary ion mass spectroscopy (ToF SIMS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and differential scanning microscopy (DSC). PVP formulations were homogeneous, with no evidence of crystallisation PEGDA/PCLDA/CBZAFM images showed a clear phase separation at the micron scale and no drug was detected at the surface. In this chapter, the production of adjustable doses was also evaluatedusing UV-VIS spectrophotometry. In chapters 4 and 5, a solvent-free hot-melt 3D inkjet printing method suitable for manufacturing solid dosage forms was developed. Excipients including beeswax, carnuba wax, gelucire 44/14 and trimyristin were examined for printability. Beeswax a naturally derived and FDA approved material showed the best printability behaviour and was selected as the drug carrier. Traditional circular shaped tablets and cylindrical implants loaded with 5% w/w fenofibrate were successfully fabricated. The printed tablets and implants were well-defined, smooth surfaced and with no apparent defects. The architecture of the tablets was investigated using 3D micro X-ray computed tomography (μCT), revealing well defined and ordered honeycomb channels in the interior of the tablets. The distribution of the drug was evaluated at the macro scale level using DSC and at the micro scale level using ToF - SIMS and Raman spectroscopy. The drug was homogenously distributed within the drug carrier (beeswax matrix ) at the microscale level. At the micron scale level, the drug was heterogeneously distributed. ToF - SIMS studies also revealed that the drug was depleted from the upper most top surfaces. Production of solid dosage forms with intricate and adaptable geometries was demonstrated by printing honeycomb architecture tablets with predetermined variable cell diameters. The diamater of the honeycomb cells was varied, in order to achieve controlled variable drug release profiles. The ablity to control drug release was only applicable above an established critical cell diameter of 0.5 mm. An analytical model describing Fickian diffusion from a slab geometry was developed to allow for the prediction of drug release from the honeycomb tablets. The predicted drug release profiles varied slightly from the experimental data, but the trends for the two data set were identical. For both data sets the rate of drug release increased with increase in the surface area to volume ratio. The findings and the developments demonstrated in this thesis provide an insight into the potential application of 3DIJP as a tool for manufacturing solid dosage forms with bespoke properties for controlled drug release but also highlights some limitations.

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3

Tennberg, Hannes. "WOODEN : in other forms." Thesis, Konstfack, Inredningsarkitektur & Möbeldesign, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-6347.

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4

Katstra, Wendy E. (Wendy Ellen) 1974. "Fabrication of complex oral drug delivery forms by Three Dimensional Printing (tm)." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/32709.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2001.
Includes bibliographical references (p. 237-241).
Three Dimensional Printing 3DPTM is a novel solid freeform fabrication technology that has been applied to the fabrication of complex pharmaceutical drug devices. Limitations of the technology as relating to pharmaceuticals have been addressed and prototype dosage forms have been fabricated. The resolution of the 3DP tablets was found to depend on particle size and liquid migration during printing and drying. The surface finish of 3DP tablets was enhanced by uniaxial pressing. Migration inhibiting additives were effective in limiting transport. Both aqueous and ethanol-based solutions showed a decrease in migration on the order of 20% when appropriate powder bed additives were introduced. Migration was also decreased by pre-printing barriers to confine secondary printed drug solutions. Low dosage forms were fabricated with as little as 2.3 nanograms. Lower dosages are expected upon dilution of the initial drug solution. Printing forms with high dosage is limited by powder void volume, filling efficiency, and drug solubility limits. Multiple print passes increased the dosage per tablet volume, 6, at the expense of process time. The use of drug suspensions to overcome solubility limits and uniaxial compression to reduce tablet volume was shown to significantly increase 6. The highest 8 achieved was 427 mg/cc for pressed suspension-printed tablets, representing 74% of the theoretical limit. Complex oral dosage forms were fabricated with 3DP to show lagged-release, extended-release, double-release, and zero-order-release. Release properties, such as lag time and release rate, were manipulated by varying the printing parameters.
(cont.) Dual-release and zero-order-release forms were fabricated using a surface degradation/erosion system based on HPMC, lactose, and EudragitÊ¾ L100. Erosion rate constants were used to model release from tablets with non-uniform drug distributions. Diclofenac and chlorpheniramine dual-release tablets were designed with 3 drug regions, and dissolution of the tablets followed the model closely, exhibiting 2 onsets. Two types of zero-order tablets were invented and fabricated by 3DP. These contained drug concentration gradients designed to complement the volumetric nonuniformity of eroding shells. Three formulations showed constant release of diclofenac sodium over 1-7 hours (9.6mg/hr), 1-15 hours (6.8mg/hr), and 1-36 hours (2.5mg/hr).
by Wendy E. Katstra.
Ph.D.

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5

Khaled, Shaban. "Extrusion based 3D printing as a novel technique for fabrication of oral solid dosage forms." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/38437/.

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Extrusion based three dimensional (3D) printing is defined as a process used to make a 3D object layer by layer directly from a computer aided device (CAD). The application of extrusion based 3D printing process to manufacture functional oral solid tablets with relatively complex geometries is demonstrated in this thesis. In Chapter 3 the viability of using a basic desktop 3D printer (Fab@Home) to print functional guaifenesin bilayer tablets (GBTs) is demonstrated. Guaifenesin is an over the counter (OTC) water soluble medicine used as expectorant for reduction of chest congestion caused by common cold and infections in respiratory system. The bilayer tablets were printed using the standard pharmaceutical excipients; hydroxypropyl methyl cellulose (HPMC) 2208, 2910, sodium starch glycolate (SSG), microcrystalline cellulose (MCC) and polyacrylic acid (PAA) in order mimic the commercial model formulation (Mucinex®) guaifenesin extended-release bilayer tablets. The 3D printed guaifenesin bilayer tablets (GBTs) were evaluated for mechanical properties as a comparison to the commercial GBTs and were found to be within acceptable range as defined by the international standards stated in the USP. Drug releases from the 3D printed GBTs were decreased as the amount of HPMC 2208 increased due to the increased wettability, swelling properties and gel barrier formation of the HPMC. The 3D printed GBTs also showed, as required, two release profiles: immediate release (IR) from the top layer containing disintegrants; SSG and MCC and sustained release (SR) profile from the lower layer containing HPMC 2208. The kinetic drug release data from the 3D printed and commercial GBTs were best modelled using the Korsmeyer–Peppas model with n values between 0.27 and 0.44. This suggests Fickian diffusion drug release through a hydrated HPMC gel layer. Other physical characterisations: X-Ray Powder Diffraction (XRPD), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), and Differential Scanning Calorimetry (DSC) showed that there was no detectable interaction between guaifenesin and the used excipients in both 3D printed and commercial GBTs. A more complex printer (RegenHu 3D bioprinter) was subsequently used to print complex multi-active tablets containing captopril, nifedipine, and glipizide as a model therapeutic combination. These drugs are frequently used to treat hypertension and diabetes mellitus. The 3D printed tablets were evaluated for drug release and showed that captopril was released by osmosis through permeable cellulose acetate (CA) film and both glipizide and nifedipine were released by diffusion through the hydrophilic HPMC 2208 matrix. According to XRPD and ATR-FTIR results, there was no detectable interaction between the actives and the used excipients. In the final experimental chapter, a combined treatment regimen: atenolol, ramipril, hydrochlorothiazide (anti-hypertensive medications), pravastatin (cholesterol lowering agent), and aspirin (anti-platelets) were printed into more complex geometry (polypill) using the RegenHu 3D bioprinter. This combined drug regimen is manufactured by Cadila Pharmaceuticals Limited as a capsule formulation under the trade name of Polycap™ and is currently the only polypill formulation commercially available and is used to treat and prevent cardiovascular diseases. The printed polypills were characterized for drug release using USP dissolution testing and showed the intended immediate and sustained release profiles based upon the active/excipient ratio used. Aspirin and hydrochlorothiazide were immediately released after the polypill contacted the dissolution medium, and atenolol, ramipril, and pravastatin were released over a period of 12 hrs. XRPD and ATR-FTIR showed that there was no detectable interaction between the actives and the used excipients. In this work, extrusion based 3D printing technique was used to print oral solid dosage forms with complex and well-defined geometries and function. The technology of 3D printing could offer the opportunity to print oral tablets with high and precise drug dosing and controlled drug release profiles tailored for sub-populations or individuals. If the manufacturing and regulatory issues associated with 3DP can be resolved such personalised medicine delivered by 3D printing could improve patient compliance and provide more effective treatment regimes.

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El, Aita Ilias [Verfasser], Jörg [Gutachter] Breitkreutz, and Peter [Gutachter] Kleinebudde. "Manufacturing solid dosage forms using pressure-assisted microsyringe 3D-printing / Ilias El Aita ; Gutachter: Jörg Breitkreutz, Peter Kleinebudde." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2021. http://d-nb.info/1232490059/34.

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7

Вихристюк, Ольга Володимирівна. "Поліграфічне підприємство з дослідженням технології виготовлення етикеткової продукції". Master's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/46346.

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Пояснювальна записка до магістерської дисертації на тему «Поліграфічне підприємство з дослідженням технології виготовлення етикеткової продукції» складається з 112 сторінок, що містять в собі 7 розділів та підрозділи. Загальна кількість ілюстрацій становить 49, таблиць – 52, кількість джерел згідно з переліком посилань 33. Магістерська дисертація складається з семи основних розділів, де детально розкрито головні технічні, конструкторські особливості етикеток, обрано необхідне обладнання та матеріали для виготовлення етикеткової продукції. Проаналізовано всі процеси виготовлення етикеткової продукції, починаючи від вибору способу друку, необхідного друкарського устаткування, додрукарських процесів, технології виготовлення друкарських форм, і закінчуючи післядрукарською обробкою. Розроблено загальну блок-схему технологічних процесів виготовлення етикеткової продукції. Розраховані основні техніко-економічні показники. Проведений аналіз патентної інформації засвідчив, що розробки по вдосконаленню технологій виготовленні етикеткової продукції проводяться й надалі. Однак в межах таких тенденцій надто мало уваги приділено саме методам контролю, що, безумовно, є актуальним напрямком подальших наукових досліджень, так як дозволить суттєво покращити якість відтворення поліграфічної продукції. В експериментальній частині магістерської дисертації здійснено постановку завдання дослідження, де визначено, що удосконалення процесу виготовлення етикеткової продукції є необхідним для покращення технології виготовлення етикеткової продукції, зокрема, було досліджено дефекти при виготовленні етикеткової продукції та досліджено колірні показники пантонних кольорів під час друкування накладу етикеткової продукції.
The explanatory note to the master's dissertation on the topic "Printing company with research on the technology of manufacturing label products" consists of 112 pages, containing 7 sections and subsections. The total number of illustrations is 49, tables - 52, the number of sources according to the list of references 33. The master's dissertation consists of seven main sections, which reveal in detail the main technical, design features of labels, selected the necessary equipment and materials for the manufacture of label products. All processes of manufacturing label products are analyzed, starting from the choice of printing method, necessary printing equipment, pre-printing processes, technology of manufacturing printing plates, and ending with post-printing processing. The general block diagram of technological processes of production of label products is developed. The main technical and economic indicators are calculated. The analysis of patent information showed that the development of improved technologies for the manufacture of label products is carried out in the future. However, within such trends, too little attention is paid to control methods, which, of course, is an important area of further research, as it will significantly improve the quality of reproduction of printed products. In the experimental part of the master's dissertation the research task was set, where it was determined that the improvement of the label manufacturing process is necessary to improve the technology of label production, in particular, defects in label manufacturing were investigated.
Объяснительная записка к магистерской диссертации по «Полиграфическое предприятие с исследованием технологии изготовления этикеточной продукции» состоит из 112 страниц, содержащих 7 разделов и подразделы. Общее количество иллюстраций составляет 49, таблиц – 52, количество источников согласно ссылкам 33. Магистерская диссертация состоит из семи основных разделов, где подробно раскрыты главные технические, конструкторские особенности этикеток, выбрано необходимое оборудование и материалы для изготовления этикеточной продукции. Проанализированы все процессы изготовления этикеточной продукции, начиная от выбора способа печати, необходимого печатного оборудования, допечатных процессов, технологии изготовления печатных форм и заканчивая послепечатной обработкой. Разработана общая блок-схема технологических процессов изготовления этикеточной продукции. Рассчитаны главные технико-экономические характеристики. Проведенный анализ патентной информации показал, что разработки по совершенствованию технологий при изготовлении этикеточной продукции проводятся и в дальнейшем. Однако в рамках таких тенденций слишком мало внимания уделено именно методам контроля, что безусловно является актуальным направлением дальнейших научных исследований, так как позволит существенно улучшить качество воспроизведения полиграфической продукции. В экспериментальной части магистерской диссертации осуществлена постановка задачи исследования, где определено, что усовершенствование процесса изготовления этикеточной продукции необходимо для улучшения технологии изготовления этикеточной продукции, в частности, были исследованы дефекты при изготовлении этикеточной продукции и исследованы цветовые показатели пантонного цвета при печатании тиража.

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8

Korte, Carolin [Verfasser], Jörg [Gutachter] Breitkreutz, Peter [Gutachter] Kleinebudde, and Julian [Akademischer Betreuer] Quodbach. "3D-Drug-Printing: Extrusion of Printable Drug-Loaded Filaments and Development of Novel Solid Dosage Forms / Carolin Korte ; Gutachter: Jörg Breitkreutz, Peter Kleinebudde ; Betreuer: Julian Quodbach." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1182032192/34.

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9

Al-Ansari, Banan Ahmed. "Interrelated Histories, Practices, and Forms of Communication: Using Arabic Calligraphy to Learn Arabic Typography." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804911/.

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In this self-study inquiry, I studied my graphic design practice in a professional setting, focusing on my Arabic typographic skills and knowledge. My roles as researcher and design educator indivisibly intertwined throughout this research. I worked to understand the value of calligraphy in art and design education, highlighting its power as an art form while also emphasizing its pedagogical potentials. I utilized two theoretical approaches suited to investigating and understanding the Arabic letters as text and image, Ibn Arabi’s science of letters, or 'ilm al-hurûf, and semiotics. I applied my theoretical framework to three distinctive artworks to investigate their uses of the Arabic letters, contemplating their roles in modern and contemporary Arab art. Essential to my research was learning Arabic calligraphy through two approaches: 1) I attended a calligraphy workshop, and 2) I conducted three self-study experimentations. I analyzed my experience through visual representations, commentary, and narrative inquiry to assess Arabic calligraphy’s significance for graphic design education. As such, my experimentations confirmed Arabic calligraphy’s aesthetic and educational value. I employed my findings to create a contemporary Arabic typography curriculum suitable for university-level students. This curriculum is built on learning theories such as visual culture analysis, semiotics, constructivist theory, play principles, and critical thinking, aiming to situate Arabic calligraphy as a modern learning model significant for typography education. Finally, I constructed a basic course for Arabic typography to support students’ development of Arabic typography fluency.

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10

Sundaram, Subramanian Ph D. Massachusetts Institute of Technology. "3D-printing form and function." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120416.

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Анотація:

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 153-171).
Integrating diverse functions inside man-made parts with specific shapes, in a highly scalable manner, is the central challenge in manufacturing. Functional integration is typically achieved by assembling specialized parts, each independently made using carefully designed production techniques - for example, in assembly lines in the automotive industry. Externally assembling specialized parts is tedious at certain length scales (e.g. mesoscale manufacturing), imposes restrictions on achievable geometries, and limits functional integration. In contrast, nature excels at packing disparate materials and functions into unconstrained geometries across different length scales (e.g. distributed sensors in cuttlefish, or sensorimotor pathways and resonant muscles in insects). These far exceed our current fabrication capabilities, and replicating all the functions of natural systems has remained a distant dream. 3D-printing has resolved many challenges in fabricating complex geometries, but despite its promise, assembling diverse materials (including solids, liquids and thin-films) and functions inside a single, printed composite is a current challenge. This thesis presents a set of materials, processes and design strategies - a full experimental toolkit - to address the question: how can we distribute diverse materials and functions in free-form geometries? First, a fully-3D-printed autonomous composite that can sense an external stimulus, process it, and respond by varying its optical transparency is described. The composite consists of seamlessly integrated solids (UV-cured polymers), thin-films (conducting and semiconducting, solvent-evaporated films), and encapsulated liquids. Techniques to engineer material interfaces are also presented in this section. A stimulus-free strategy to 3D-print self-folding composites at room temperature is presented in the second part of this thesis. Specifically, the focus is on printing flat electrical composites that fold into pre-programmed shapes after printing using residual stress defined in specific regions. This provides advantages in the fabrication speed, and also expands the range of achievable geometries when using solvent-based inks. The third portion of this thesis focuses on 3D-printing soft actuators. After highlighting a few example applications of printed actuator arrays, this is used as a case study for topology optimization based design strategies. It is shown that the inclusion of a topology optimizer in the 3D-printing pipeline enables the automated design and fabrication of high-dimensional designs. The final section of this work focuses on creating tactile sensor arrays, with an emphasis on the acquisition of tactile datasets that can be used to understand the human grasp. The concluding section summarizes the role of the fabrication strategies presented here in creating composites of increasing levels of autonomy and self-sufficiency.
by Subramanian Sundaram.
Ph. D.

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Leines, Kevin B. "The influence of the position of a color control bar on a form when determining the most appropriate location to measure variability in solid ink density and dot gain of a printed product /." Online version of thesis, 1990. http://hdl.handle.net/1850/10926.

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12

Velebskaja, Aliona. "Fleksografinių spausdinimo formų paruošimo procesų tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100619_142601-44034.

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Анотація:

Magistro studijų baigiamajame darbe išanalizuoti fleksografinių spausdinimo formų gamybos procesai, išnagrinėti ir atskleisti vaizdų rastravimo ypatumai, detaliai aprašyta originalo (projekto) paruošimo spausdinimui eiga ir spausdinimo formų gamyba. Eksperimentiškai ištirta rastravimo proceso režimų įtaka spausdinimo formų kokybei naudojant skirtingas skaitmenines plokštes. Nustatytos geriausios rastravimo programų versijos atskiriems atvejams.
In the MS thesis are analyzed procedures of the flexographic printing plates manufacturing. The peculiarities of the screening processes are revealed. The details of the workflow of the preparation of the originals (projects) for printing and the process of printing plates manufacturing are described. Experimentally is investigated the influence of the screening regimes on the quality of the printing plates using different photopolymeric plates. The best versions of the screening program for the particular cases were determined.

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Abd, El Kader Magdy Ezzat. "Application of Hot-Melt Ink Jet Processes for Imaging at Offset Printing Form Cylinder." Doctoral thesis, Universitätsbibliothek Chemnitz, 2004. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200400092.

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The present work related to apply hot-melt ink-jet process for imaging at offset lithographic printing form, to utilise a reusable surface for many times and particularly related to validating thermal and ultrasonic erasing processes. This dissertation investigated systematically the role of certain factors towards affecting erasing image area process on print surfaces. Thermal erasing process approved to melt and suck the image area from the surface, the results were adopted by using contact angle measurements and scanning electron microscope. Ultrasonic erasing process permitted to solve the image area by choosing erasing chemistries, influence of selected erasing chemistries on printing surface, and evaluation the process, the results were tested by UV/Vis spectrometer, contact angle, profileometery and visual microscope
Der Fortschritt im Bereich von Charakterisierung und Verständnis für Hot-melt Ink Jet Prozesse zur Bebilderung von Offsetdruckform-Zylindern ist ein Ergebnis dieser Forschung. Die Systematik dieser Arbeit basiert auf einem theoretischen Teil, um einen geeigneten Löschprozess auszuwählen. Der Löschprozess hängt von den Eigenschaften des Hot-melt Ink Jet Materials und der genutzten Aluminiumdruckoberfläche ab. Diese werden systematisch im Labormaßstab experimentell untersucht. Der thermische Prozess wurde einerseits durch Benetzbarkeitsprüfungen und anderseites durch Rasterelektronmikroskopaufnahmen bewertet.Der Ultraschallprozess ist ein nasser Löschprozess. Die Untersuchungen wurden in vier Stufen systematisch durchgeführt - Auswahl vom geeigneten Lösungsmitteln - Einflüsse von ausgewählten Lösungsmitteln auf nicht beschichtete und beschichtete Aluminium platten - Evaluation eines Ultraschalllöschprozesses - Validation eines Löschprozesses; zur Bewertung des Löschprozesses wurden mehrere Druckplattenproben bebildert und gelöscht Die Ergebnisse wurden durch UV/Vis Spektrometer, Kontaktwinkel, Profiliometrie und Visuelle Mikroskopie getestet

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Abd-el-Kader, Magdy Ezzat. "Application of hot melt ink jet processes for imaging at offset printing form cylinder." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=970645775.

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15

Al-Hachami, Wathiq. "Investigation of pico-litre inkjet printing for nano-gram scale solid form screening of pharmaceuticals." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52031/.

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The tendency of the majority of active pharmaceutical ingredients (APIs) to exist in different solid forms with keeping their chemical structures is called polymorphism. This phenomenon has gained a lot of interest in the pharmaceutical industry, hoping to avoid producing unexpected transformations of compounds during and after synthesis. The optimal way to avoid that is to subject the API, at the early stage of development, under various conditions in order to obtain an elegant (safe, effective, and stable) drug for the next formulation step. The aim of this thesis was to investigate some factors that affect the appearance of different polymorphs during screening of some APIs. Four model drugs were selected: paracetamol; carbamazepine; mefenamic acid; and flufenamic acid. All have been well-characterised previously in terms of solid-state forms. Piezoelectric, or 2D inkjet printing technique was used as a main technique in fabrication of nanoarrays of APIs onto predefined design on a solid tunable substrates because of its ability to control the delivered quantities of the the printed materials accurately, without any direct contact with the used substrate that may cause a sample cross-contamination. Light optical microscope was used to investigate the behaviour of the printed droplets during and after solvent evaporation and turn to dried spots, and to confirm the crystalline state of some spots by using the polarised light in the same microscope. Raman spectroscopy at low-wavenumber, or phonon region (40-400 cm-1) was used for the first time to identify the resulted polymorphs after the printing process as its ability to probe the alterations that happen in the molecular skeleton inside the crystal lattice , in addition to molecular region (400-1800 cm-1) to analyse the resulting spots. In chapter three, the piezoelectric inkjet printing technique was successfully used for the first time to miniaturise, screen, and study the stability of the APIs at nano quantities in the range of (1-500 ng), about six-ordered magnification less than the reported studies. It was found that the variation in the printed quantities can produce different states and polymorphs. Stability with time was also studied for all the printed samples and it was noticed the variation in time for some printed drugs to convert from solid amorphous to crystalline state. In chapter four, the advantage of the ability of the gold-coated slide to undergo further chemical modifications was exploited to create new substrates. Chemical modification of the gold substrates was carried out by treating them with two types of thiols to form self-assembly monolayers (SAMs) and use them as substrates in polymorph screening of some APIs. The new prepared SAMs were examined by preliminary tests like atomic force microscope (AFM) and water contact angle (WCA) measurements to investigate the texture of the new substrates before using them in printing process. It was found that changing the chemical structure of the substrate can lead to different polymorphs. In chapter five, an attempt to create highly hydrophobic substrates was done to investigate whether it can affect the propensity of APIs for polymorphism. Fluorinated compounds were used in this chapter as they are considered more hydrophobic than the substrates used in the previous part of the work The effect of the fluorinated substrates on appearance of new polymorphs was studied. Two fluorinated compounds were selected for preparation of high-water repellent surfaces and using them as substrates as they have the ability to limit the spreading of the printed droplets of the API, and allow the molecules to be constructed layer by layer and form a condense spot. The new fluorinated substrates were examined before using them in printing, and they exhibited high WCA. Another FLUF polymorph (VI) was investigated in addition to the two reference (I and III) polymorphs used in FLUF polymorphic screening. It was found that the intensity of the Raman peaks of the printed spots of APIs was good and clear to recognise when using fluorinated SAMs as a substrate, while the fluorinated substrate prepared from Flutec LE15 exhibited fluorescence effect due to the interactions between the glass and the drug’s spot spectrum.

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Gissibl, Timo [Verfasser], and Harald [Akademischer Betreuer] Giessen. "3D printing of sub-micrometer accurate ultra-compact free-form optics / Timo Gissibl ; Betreuer: Harald Giessen." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1183678215/34.

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17

Xu, Shang. "Investigations into the Form and Design of an Elbow Exoskeleton Using Additive Manufacturing." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103204.

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The commercial exoskeletons are often heavy and bulky, thus reducing the weight and simplifying the form factor becomes a critical task. This thesis details the process of designing and making a low-profile, cable-driven arm exoskeleton. Many advanced methods are explored: 3D scanning, generative design, soft material, compliant joint, additive manufacturing, and 3D latticing. The experiments on TPU kerf cut found that the stress-strain curve of the sample can be modified by changing the cut pattern, it is even possible to control the linear region. The TPU TPMS test showed that given the same volume, changing the lattice parameters can result in different bending stress-strain curves. This thesis also provides many prototypes, test data, and samples for future reference.
Master of Science
Wearing an exoskeleton should be easy and stress-free, but many of the available models are not ergonomic nor user-friendly. To make an exoskeleton that is inviting and comfortable to wear, various nontraditional methods are used. The arm exoskeleton prototype has a lightweight and ergonomic frame, the joints are soft and compact, the cable-driven system is safe and low-profile. This design also brings aesthetics to the exoskeleton which closes the gap between engineering and design.

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Šimėnas, Mindaugas. "Ofsetinių spausdinimo formų paviršinių savybių tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2006~D_20060616_153055-46277.

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It was investigated characteristics of surfaces of offset printing plates. A method of measurement of wetting angle was improved and there were investigated the wetting characteristics of hydrophilic surfaces of offset printing plates and their dependence on dampening solution and on printed run. Experimentally investigated 16 offset printing plates. Wetting angle increases with the run. Surface roughness was investigated using profilograph. Changes of surface roughness during printing were determined and it was found that during printing quantity of bigger over 1 µm irregularities increases.

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Hergel, Jean. "Synthèse de formes fabricables à partir de spécifications partielles." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0003/document.

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Les techniques de fabrication rapide, issues des techniques de prototypage rapide comme l’impression 3D ou la découpe laser permettent de fabriquer des pièces uniques sans demander d’expertise particulière du procédé mis en œuvre. En revanche la modélisation de nouveaux objets tout comme la personnalisation d’objets existants restent difficiles. En effet, les techniques de prototypages rapides imposent des contraintes sur la géométrie du modèle qui doivent être respectées. Cette thèse présente un ensemble de techniques qui ont pour point commun d’assister l’utilisateur dans la modélisation d’un objet, en tenant compte des contraintes du procédé qui permettra de le fabriquer. À cette fin, l’algorithme prend en charge tout ou partie de la modélisation. En particulier, les problématiques suivantes sont abordées : Tout d’abord, je propose d’améliorer la qualité des objets fabriqués avec une imprimante 3D en minimisant certains défauts qui apparaissent lors de la fabrication. Les approches développées modifient uniquement les algorithmes de pilotage de l’imprimante. En second lieu, je propose d’aider l’utilisateur à prendre en compte les contraintes de fabrication pendant la modélisation. Mes techniques utilisent des informations partielles sur la forme que l’utilisateur souhaite fabriquer, comme le dessin en deux dimensions d’un mécanisme, ou un modèle paramétrique qui définit un meuble. L’algorithme optimise une forme finale qui améliore des critères liés à sa fabrication (gaspillage, encombrement, etc.). Enfin, dans certains cas (e.g. grand public) l’utilisateur n’est pas forcément à même de modéliser ces formes via des logiciels spécialisés. Pour ce cas précis, je propose une technique de synthèse de meubles à partir de spécifications fonctionnelles, e.g. la spécification de poids à porter dans l’espace
The Rapid Manufacturing techniques that emerged from Rapid Prototyping techniques such as 3D printing or laser cutting allow to fabricate unique objects. However, the design of those objects with existing CAD software remain a difficult task: rapid prototyping processes impose constraints on the geometry of the model. This thesis presents a set of techniques that assist the user in the design of an object by taking into account the constraints of the fabrication process. To achieve this, the algorithm automatically performs part of the modelling process. The following problems have been tackled: First, I propose to improve the quality of 3D printed objects by minimizing defects that appear during the fabrication. The technique developed impacts only the algorithm that drives the printer. Then, I propose to help the user to take into account the fabrication constraints during the modelling process. My techniques rely on partial information about the shape that the user wants to fabricate like the 2D sketch of a mechanism or a parametric model of a furniture. The algorithm optimizes the initial shape to improve fabrication objectives(Wastage, etc.) Finally, in some cases, the user does not know how to operate dedicated software. In this case, I propose a synthesis technique of furniture from functionnal specification, e.g. loads that have to be supported in space

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Svatík, Juraj. "Funkční pěny s gradientem hustoty." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401848.

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Vycházíme-li z lehčených přírodních materiálů, lze od porézních materiálů s gradientem porozity očekávat mechanické vlastnosti nadřazené konvenčím polymerním pěnám, a to díky jejich specifické architektuře. Tyto vlastnosti umožňují použití lehčených materiálů jako strukturních prvků. V této práci je popsaná příprava gradientních porézních materiálů pomocí laminování a/nebo 3D tisku. Provedeny byly statické a dynamické mechanické testy na obou kvazi homogenních a gradientně porézních pěnách poskytující experimentální podklad pro hypotézu deformační odezvy plynoucí ze strukturní architektury. Data se interpretovala užitím zavedených teoretických modelů. Naše výsledky vedly k závěru, že tyto teoretické modely odvozené od pěn s pravidelnou strukturou není vhodné aplikovat pro pěny s gradientem porozity, protože prokazují podstatně lepší mechanické vlastnosti než homogenně porézní pěny.

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Roman, Julien. "Mise en forme de matériaux carbonés biosourcés par voie liquide." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0202/document.

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Ce travail de thèse est consacré à la mise en forme de nouveaux matériaux carbonés à partir d’un précurseur biosourcé. Les matériaux carbonés tels que les fibres de carbone utilisés dans les composites sont principalement obtenus à partir de précurseurs d’origine pétrosourcée. Ces précurseurs sont onéreux et incompatibles avec une industrie durable. L’utilisation d’un précurseur biosourcé disponible en grande quantité tel que la lignine permet de pallier ces limitations. La structure moléculaire aromatique et la teneur élevée en carbone de la lignine font d’elle un candidat idéal pour l’élaboration de matériau carboné biosourcé. La lignine a pu être transformée en divers matériaux carbonés tels que des nanofibres de carbone, des tresses de nanofibres de carbone, ou encore des objets 3D composites carbonisés. Ces matériaux ont été obtenus à partir de techniques innovantes que sont l’électrofilage et l’impression 3D. Le tressage des nanofibres de carbone ex-lignine a permis d’évaluer les propriétés mécaniques des fibres de carbone. Les propriétés électrochimiques des tresses de nanofibres de carbone ex-lignine sont apparues intéressantes pour une utilisation potentielle en tant que microélectrodes. La microstructure faiblement organisée du carbone issue de la lignine a pu être améliorée. Un traitement thermique de graphitisation ou un ajout de nanocharges carbonées ont contribué à cette amélioration. Les propriétés mécaniques, structurales et de conductivité électrique des nanofibres nanocomposites ont permis de définir l’influence de l’oxyde de graphène sur la lignine. Un effet composite entre ces deux constituants a pu être observé. L’impression 3D d’encres composites à base de lignine et d’oxyde de graphène a pu être rapportée pour la première fois afin d’élaborer des objets 3D carbonisés denses, organisés et conducteurs d’électricité
This work is devoted to the preparation of new bio-based carbon materials. Carbon materials, such as carbon fibers used in composites, are mainly obtained from a petroleum precursor. These precursors are expensive and not compatible with a sustainable industry. The use of a bio-based precursor available in large quantities such as lignin makes it possible to overcome limitations of petroleum based precursors. The aromatic molecular structure and high carbon content of lignin make it an ideal candidate for the production of bio-based carbon material. Lignin could be transformed into various materials such as carbon nanofibers, twisted carbon nanofibers, or carbonized composite 3D structures. These materials have been obtained from innovative techniques such as electrospinning and 3D printing. Twisting of the lignin-based-carbon nanofibers allowed for measurements of their mechanical strength. The electrochemical properties of the lignin-based twisted carbon nanofibers are interesting for potential microelectrode applications. The low microstructural order of the carbon from the carbonized lignin has been improved. Graphitization treatment or addition of carbon nanofillers contributed to this improvement. The mechanical, structural and electrical properties of nanocomposite carbon nanofibers illustrate the influence of graphene oxide on lignin. A composite effect between these two components has been observed. The 3D printing of composite inks based on lignin and graphene oxide has been reported for the first time in order to elaborate dense, organized and electrically conductive 3D carbonized structures

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Raimondo, Luna. "La stampa 4D e gli smart materials. Stato dell’arte e progettazione di un kit per scrittura Braille basato su fogli polimerici a memoria di forma." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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Negli ultimi anni, l'additive manufacturing ed in particolare le metodologie di stampa 4D, hanno subito un forte boost di interesse nella ricerca, soprattutto con l'ausilio di smart materials. Le applicazioni della stampa 4D atrtaverso smart materials vanno dall'idraulica all'ingegneria bio-medica, fino ad elementi atti a ottimizzare le prestazione energetiche degli edifici. In questa tesi si presenta una literature review dei topic principali associati alle tecnologie dell'additive manufacturing e alle metdologie di stampa 4D e si propone il progetto PUNTA, un punteruolo per sistema Braille ideato per imprimere e cancellare caratteri in un foglio costituito dal polimero a memoria di forma MM4520.

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Dickman, Daina Elizabeth. ""I'd created my own truths by printing my zine." Women-written Perzines as a narrative form for disclosure and advice giving." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406717512.

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Jolly, Nicolas. "Filtres accordables volumiques à forts facteurs de qualité pour des applications spatiales." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0103/document.

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A l'heure où la demande en quantité d'informations et le nombre d'utilisateurs explosent, toujours avec des limitations en allocation en fréquence et bande passante, les systèmes de télécommunication tendent à optimiser la gestion de leur capacité en s'orientant vers des systèmes reconfigurables. Dans le cas des filtres d'OMUX, apporter de l'accordabilité en conservant d'excellentes performances électriques, thermiques et mécaniques soulève de nombreuses difficultés.Nous avons dans un premier temps démontré la faisabilité sur un filtre à saut de canal à bande passante constante par le biais d'une cavité métallique chargée par un perturbateur en alumine en mouvement de rotation. Ensuite, nous avons proposé des solutions pour avoir un contrôle de la fréquence et de la bande passante en se basant sur la translation de matériaux diélectriques. Les facteurs de qualité mis en jeu sont de l'ordre de la dizaine de milliers. Enfin nous avons tiré profit de l'évolution des technologies d'impression plastique 3D pour valider différents concepts de filtres accordables
At a time when the amount of information and the number of users go through the roof in telecommunication market, the telecommunication systems tend to improve the management of their capacity by moving toward reconfigurable RF devices. However frequency and bandwidth allocated are still restricted. Regarding tunable OMUX filters, the actuation systems generally degrade the overall performances of the device and raise questions in terms of mechanic and thermic.We first demonstrated the feasability of a two state filter with constant narrowband, using a dielectric material (alumina) in rotation inside a metallic housing. Then, we suggested solutions to control both frequency and bandwidth with the translation of a ceramics. We deal with quality factor in the range of ten of thousands for these applications. Eventually, we validated some principle for tunable filters thanks to the efficiency of 3D plastic printer

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Correia, Rodrigo Emanuel de Almeida. "De que forma estão os retalhistas a incorporar aplicações 3D no seu modelo de negócio? Caso de estudo." Master's thesis, Instituto Superior de Economia e Gestão, 2019. http://hdl.handle.net/10400.5/19203.

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Mestrado em Gestão e Estratégia Industrial
Com os recentes desenvolvimentos tecnológicos cada vez de ciclos mais reduzidos aliados a uma incessante busca pela inovação, as empresas necessitam de tomar decisões que as permita distanciar-se e ao mesmo tempo diferenciar-se da concorrência. A tecnologia de impressão 3D é um tema cada vez mais discutido ao longo dos últimos anos pelas suas características promissoras face à manufatura tradicional, em grande parte potenciadas pelos avanços tecnológicos referidos anteriormente. No entanto, poucos estudos existem sobre a sua aplicação em outros contextos empresariais, como o caso do contexto retalhista. Ainda que existam alguns estudos abrangendo as aplicações da tecnologia em determinadas fases da cadeia de valor de uma empresa, são desconhecidos estudos que permitam analisar a impressão 3D no contexto retalhista na forma de serviço. A presente investigação pretende evidenciar as diferenças existentes no modelo de negócio de uma empresa retalhista antes e depois da implementação da tecnologia de impressão 3D. Para esse efeito, utilizou-se um modelo de análise que permitiu contrastar as diferenças ao nível do modelo de negócio e ao mesmo tempo equiparar os resultados com a literatura encontrada sobre o tema. Segundo os dados analisados, é possível chegar à conclusão de que a impressão 3D permitiu reestruturar o modelo de negócio existente na empresa de forma positiva, alterando todas as componentes que o compõem, permitindo também obter conclusões relativamente à sua viabilidade em contexto nacional.
With the recent technological developments in ever-shrinking cycles coupled with a relentless pursuit for innovation, companies need to make decisions that allow them to distance themselves while differing from the competition. 3D printing technology has been a subject that has been increasingly discussed over the last few years for its promising characteristics compared to traditional manufacturing, greatly enhanced by the technological advances. However, few studies exist about its application in other business contexts, such as the retail context. Although there are some studies covering the applications of technology in certain phases of the value chain of a company, studies that analyze 3D printing in the retail context as a service are unknown. This research aims to highlight the differences in the business model of a retail company before and after the implementation of 3D printing technology. For this, we used an analysis model that allowed us to contrast the differences at the business model level and at the same time to match the results with the literature found on the subject. According to the data analyzed, it is possible to conclude that 3D printing made it possible to restructure the existing business model in the company in a positive way, changing all its components, and also allowing conclusions to be reached regarding its feasibility in a national context.
info:eu-repo/semantics/publishedVersion

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Liu, Eunice. "Design gráfico: processo como forma." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/16/16134/tde-14102013-154730/.

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Criatividade no uso de recursos de impressão, reprodução, gravação, acabamento gráficos, editorial, encadernação e materiais, em design gráfico, denominados processos, é o tema desta pesquisa. A investigação procede de projetos resultantes da prática disciplinar e é documentada por imagem, fotografias, para ciência visual. Estudos técnico, formal (relativo à forma) e projetual investigam relações entre processo e forma, resultando em um repertório de parâmetros e possibilidades. Forma pura é gráfica e a construída, matéria conformada por processos, meios de produção pelos quais se trabalha forma. Conhecimentos de processos são recursos de projeto, e apropriações criativas destes, qualificam um bom design
Creativity in the use of printing, reproduction, engraving, graphic finishings, editorial, binding and material resources in graphic design, denominated processes, is the theme of this research. The investigation is originated by projects, product of disciplinary practice, and is documented by image, for visual science. Technical, formal (related to form), and project studies explore relationships between process and form, resulting in a repertoire of parameters and possibilities. Pure form is graphic and constructed form, material shaped by processes, means of production by which form is tooled. The knowledge of processes is project resources, and creative appropriations of them, qualify a good design

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Živko, Pavlović. "Karakterizacija površinske strukture neštampajućih elemenata CtP termalne štamparske forme za ofset štampu." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2012. http://dx.doi.org/10.2298/NS20120519PAVLOVIC.

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Disertacija daje pregled novih i relevantnih istraživanja i stavovau naučnoj zajednici na temu štamparskih formi i uticaja procesaštampe na trošenje neštampajućih elemenata. U disertaciji jeukazano na kontinualno praćenje topografskih promenaneštampajućih elemenata štamparskih formi kako bi se kontrolisaoperiod eksploatacije a time i proces reprodukcije. Takođe dajeprilog novim istraživanjima sa analizom velikog brojaeksperimentalnih uzoraka sa dobijenim izmerenim podacima iodgovarajućim korelacijama i predstavlja napredak u shvatanjumehanizma trošenja neštampajućih površina štamparskih formi injihov uticaj na tribološke promene u odnosu na strukturu osnovealuminijuma i sloja aluminijum oksida.
Dissertation gives an overview of the current state, research and theories ofprinting forms and influence of printing process on wearing of non-printingelements within the science community. The dissertation points out the continuousmonitoring of topographic changes of printing form non-printing elements to controlthe exploitation of a period of time and the process of reproduction. This workcontributes to new research with the analysis of large number of experimentalsamples and calculated correlations and represents an advance in thecomprehension of the surface wear mechanism of printing form non-printingelements and their influence on the tribological changes to the structure of thebase layer of aluminium and aluminium oxide.

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Dumas, Jérémie. "Synthèse de formes contrôlable pour la fabrication digitale." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0008/document.

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L’objet principal de cette thèse est de proposer des méthodes pour la synthèse de formes qui soient contrôlables et permettent d’imprimer les résultats obtenus. Les imprimantes 3D étant désormais plus faciles d’accès que jamais, les logiciels de modélisation doivent maintenant prendre en compte les contraintes de fabrication imposées par les technologies de fabrication additives. En conséquence, des algorithmes efficaces doivent être développés afin de modéliser les formes complexes qui peuvent être créées par impression 3D. Nous développons des algorithmes pour la synthèse de formes par l’exemple qui prennent en compte le comportement mécanique des structures devant être fabriquées. Toutes les contributions de cette thèse s’intéressent au problème de génération de formes complexes sous contraintes géométriques et objectifs structurels. Dans un premier temps, nous nous intéressons à la gestion des contraintes de fabrication, et proposons une méthode pour synthétiser des structures de support efficaces qui sont bien adaptées aux imprimantes à filament. Dans un deuxième temps, nous prenons en compte le contrôle de l’apparence, et développons de nouvelles méthodes pour la synthèse par l’exemple qui mélangent astucieusement des critères sur visuels, et des contraintes sur le comportement mécanique des objets. Pour finir, nous présentons une méthode passant bien à l’échelle, afin de contrôler les propriétés élastiques des structures imprimées. Nous nous inspirons des méthodes de synthèse de texture procédurales, et proposons un algorithme efficace pour synthétiser des microstructures imprimables et contrôler leurs propriétés élastiques
The main goal of this thesis is to propose methods to synthesize shapes in a controllable manner, with the purpose of being fabricated. As 3D printers grow more accessible than ever, modeling software must now take into account fabrication constraints posed by additive manufacturing technologies. Consequently, efficient algorithms need to be devised to model the complex shapes that can be created through 3D printing. We develop algorithms for by-example shape synthesis that consider the physical behavior of the structure to fabricate. All the contributions of this thesis focus on the problem of generating complex shapes that follow geometric constraints and structural objectives. In a first time, we focus on dealing with fabrication constraints, and propose a method for synthesizing efficient support structures that are well-suited for filament printers. In a second time, we take into account appearance control, and develop new by-example synthesis methods that mixes in a meaningful manner criteria on the appearance of the synthesized shapes, and constraints on their mechanical behavior. Finally, we present a highly scalable method to control the elastic properties of printed structures. We draw inspiration from procedural texture synthesis methods, and propose an efficient algorithm to synthesize printable microstructures with controlled elastic properties

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Režnáková, Ema. "Příprava a charakterizace lehčených polymerních materiálů s hierarchickou celulární strukturou." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-414127.

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The asymmetrical arrangement of cellular structure allows for an accurate functional adaptation at all levels of hierarchy, which derives excellent features for the development of new materials. The main objective of introducing a hierarchy into cellular structures is to improve the mechanical behaviour of the material while maintaining its elastic properties. A part of this work is devoted to the literature review related to the lightened cellular polymeric materials with hierarchical cellular structure. The rest is focused on the preparation of PLA based polymer structures using 3D printing, followed by a saturation in CO2 and a foaming in a silicon oil at elevated temperature. Samples were prepared from natural and white PLA filaments. Based on a series of experiments, optimal conditions for the saturation and foaming process were identified. Through 3D printing and foaming, a one-, two- and three-level hierarchy was introduced into the beam-shaped samples and the effect of the internal cell arrangement on the strain response of the material was examined by the means of a mechanical three-point bending test. Increasing the level of the hierarchy led to an increase in material resistance, which resulted in high values of strength and strain energy (toughness) based on the samples density. The best results were achieved by samples with “sandwich” structure with three levels of hierarchy and 30% filling. Despite the shorter plateau, there was a significant increase in strength and strain energy compared to gradient structures. At the same time, the contribution of the polymer structures prepared in this field of research was demonstrated by comparison with the theoretical model.

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Garnault, Tristan. "Frittage par micro-ondes de céramiques mises en forme par impression 3D." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALI077.

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Cette thèse traite du frittage par chauffage micro-ondes de céramiques d’alumine et de zircone yttriée, mises en forme par fabrication additive (Robocasting). Le chauffage par micro-ondes permet d’appliquer des cycles thermiques courts avec un coût énergétique modéré lorsqu’on le compare aux méthodes de chauffage conventionnel. La combinaison de l’impression 3D et du frittage par micro-ondes est un processus complet, adapté à la mise en forme et à la densification de petites séries de pièces complexes, économe à la fois en matière première, en temps et en énergie. Ces travaux visent donc à coupler de manière fiable ces deux procédés en améliorant notre compréhension des interactions micro-ondes/matière, et en développant des méthodes de régulation et dispositifs de frittage adaptés.La problématique de la régulation automatique et du contrôle de la température des dispositifs micro-ondes a été tout d’abord traitée. L’instabilité en fréquence des sources magnétron est un frein à l’application d’un pilotage automatique efficace s’il n’est pas pris en considération. Par la suite, le couplage micro-onde de l’alumine et de la zircone a été discuté. Ces deux matériaux présentent des comportements très différents. L’alumine, quasi transparente, chauffe difficilement sous irradiation directe. La zircone, quant-à-elle, présente un comportement qui évolue fortement avec la température, passant de peu absorbant à réfléchissant, rendant la maitrise de son chauffage direct compliqué. Tenant compte des caractéristiques des dispositifs micro-ondes et du comportement des matériaux, il est proposé une méthode de chauffage par micro-ondes assisté, permettant le frittage rapide et maitrisé de pièces à compositions et géométries variées. Des pièces complexes ont été frittées avec succès par le procédé ainsi développé
This PhD thesis deals with the sintering by microwave heating of alumina and yttria doped zirconia ceramics, shaped by additive manufacturing (Robocasting). Microwave heating allows to apply short thermal cycles with a moderate energy cost in comparison with conventional heating method. The combination of 3D printing and microwave sintering is a complete processing route, suitable for shaping and densification of small series of complex parts, saving raw material, time and energy. The aim of this work is therefore to reliably couple these two processes by improving our understanding of microwave/matter interactions, and by developing regulation methods and adapted sintering devices.The methods of automatic regulation and temperature monitoring of microwave devices were first dealt with. The frequency instability of magnetron sources is an obstacle to the application of effective automatic control if it is not taken into account. Subsequently, the microwave coupling of alumina and zirconia was discussed. These two materials have a very different behaviour. Alumina, which is quasi-transparent, heats with difficulty under direct irradiation. Zirconia, on the other hand, has a behaviour that changes strongly with temperature, going from not very absorbent to reflective, making it difficult to control its direct heating. Taking into account the characteristics of microwave devices and the behaviour of materials, a method of assisted microwave heating is proposed, allowing the rapid and controlled sintering of parts with varied compositions and geometries. Complex parts have been successfully sintered using this process

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31

Zhang, Chuan. "Aluminum foams composite : elaboration and thermal properties for energy storage." Thesis, Troyes, 2017. http://www.theses.fr/2017TROY0015/document.

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L'objectif de cette thèse est d'étudier et d'optimiser le processus de fabrication des mousses métalliques et le comportement thermique du matériau de la mousse d'aluminium/matériau de changement de phase (MCP) par des méthodes expérimentales et numériques. Le processus d’élaboration de la mousse d’aluminium à pore ouvert est développé et optimisé pour contrôler précisément les paramètres de fabrication. Deux modèles de mousse d'aluminium à haute porosité (MAHP)/MCP composite et à faible porosité (MALP)/MCP composite sont établis pour la simulation numérique. En simulant le processus de fusion d'un système de stockage d'énergie, les composites MAHP/MCP et MALP/MCP sont comparés numériquement afin d'évaluer la performance de stockage d'énergie thermique. Les résultats montrent que la mousse d'aluminium améliore nettement le processus de transfert de chaleur dans MCP en raison de sa haute conductivité thermique. La porosité des mousses d'aluminium influence non seulement le processus de fusion du composite mais aussi la performance de stockage d'énergie thermique. Grâce à la collaboration avec EPF, une nouvelle méthode d’élaboration des mousses périodiques d'aluminium à pore ouvert est développée dans cette thèse sur la base d’impression 3D. Le comportement thermique des mousses d'aluminium périodiques à pore ouvert/MCP est analysé expérimentalement et numériquement
The objective of this thesis is to study and optimize the manufacturing process of metal foams and the thermal behavior of the aluminum foam/phase change material (PCM) composite by experimental and numerical methods. The manufacturing process of open-cell aluminum foam is developed and optimized to precisely control the parameters of mufacturing. Two pore-scale models of high porosity aluminum foams (HPAF)/PCM composite and low porosity aluminum foams (LPAF)/PCM composite are established for numerical simulation. By simulating the melting process of a layer energy storage system, the HPAF/PCM and LPAFS/PCM composite are compared numerically in order to evaluate the energy storage performance. The results show that aluminum foam improves greatly the heat transfer process in PCM due to its high thermal conductivity. The porosity of aluminum foams could not only influence the melting process of composite but also the energy storage performance. Thanks to the collaboration with EPF, a new manufacturing method of periodic open-cell aluminum foams is developed based on 3D rapid tooling. The thermal behavior of the periodic open-cell aluminum foams/PCM composite is experimentally and numerically analyzed

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32

Kaloda, Vít. "Výroba částí prototypových forem s využitím metod rapid prototyping." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417084.

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The diploma thesis pointed out the possibility of using rapid prototyping methods in the field of plastic injection, specifically to make shaped inserts into the injection mold. The universal frame of the injection mold was used and only the shaped inserts were changed. The main part of the work was the construction of an injection mold with the subsequent practical production of shaped inserts for a specified part. In the introductory part, a theoretical search was performed, about which production methods in combination with suitable materials could be theoretically used. Furthermore, the polyjet and DLP methods were chosen, which were used to produce components (core and cavity). The result of the diploma thesis was a summary of all parameters, comparison of materials and production methods. Polypropylene and polyamide 6 materials were injected into the injection mold, from which the first prototype products were made. Instructions for the production of shaped inserts with the recommended technology and material were created for the selected type, which could be used in practice.

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33

Gráf, Radomír. "Návrh technologie výroby plastového programového kotouče." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230863.

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This thesis is concerned with the appropriate design of manufacturing technology for plastic program disc including the design of plastic printing technology. At the beginning of this thesis was made an analysis of requirements for manufactured device including selection of the most appropriate technology for its manufacturing – plastic injection. In the theoretical part are described all skills needed for designing and construction of the injection mould. Partial theoretical parts are concerned with the issue of plastic materials, tools and engines for injection, and of plastic printing technology. Practical part is concerned with description of design of each single system inside the injection mould including calculation. On the basis of these calculations was selected the appropriate injection engine. The end of the practical part is concerned with the selection of the appropriate engine for printing on the plastic device which is manufactured by the technology of plastic injection. For construction of the injection mould were applied normalities of the Hasco Company and the 3D CAD system Solidworks. The conclusion of this thesis achieves the technical- economical evaluation for manufacturing of designed plastic device.

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34

Bossard, Cédric. "Elaboration et caractérisation d’un hybride organominéral à base de polycaprolactone et de bioverre sous forme de mousse macroporeuse pour la régénération osseuse." Thesis, Université Clermont Auvergne‎ (2017-2020), 2018. http://www.theses.fr/2018CLFAC068/document.

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L’accroissement de l’espérance de vie s’accompagne d’une détérioration de l’état de santé général des seniors et d’une recrudescence des maladies chroniques. Parmi les manifestations de la sénescence, l’atteinte de l’appareil locomoteur est particulièrement invalidante et accélère considérablement l’entrée en dépendance. C’est également le cas chez les plus jeunes lors d’atteintes traumatiques ou pathologiques. Ainsi, au niveau mondial 2,2 millions de greffes osseuses sont pratiquées chaque année, mais le taux de complications post-opératoires demeure élevé et est estimé à 15 % des interventions. Ces faits dessinent les contours d’un enjeu sociétal majeur ; les matériaux d’origine animale posent des problèmes d’histocompatibilité, de pathogénicité et donc de rejet. C’est pourquoi les efforts de recherche ciblent prioritairement le développement de biomatériaux synthétiques aptes à promouvoir la régénération osseuse. Actuellement les principaux substituts osseux sur le marché sont les « céramiques » bioactives (phosphates de calcium, verres bioactifs) qui présentent comme caractéristiques d’être biocompatibles, de se lier spontanément aux tissus osseux, de promouvoir l’adhésion des cellules osseuses et enfin d’être biorésorbables. Cependant, malgré cet ensemble de caractéristiques très satisfaisantes, la fragilité de ces matériaux en limite les applications. Pour pallier ce défaut, une solution ingénieuse est de s’inspirer de la structure particulière du tissu osseux. Celle-ci mêle intimement une phase inorganique, le minéral osseux constitué de cristaux d’apatite (phosphate de calcium résorbable), à une phase organique qui est majoritairement du collagène. De manière remarquable, une telle structure associe la rigidité de la partie inorganique à la ténacité des fibres de collagène. Pour obtenir des implants aux propriétés mécaniques proches du tissu osseux, la stratégie consiste donc à combiner céramiques bioactives et matière organique. À cette fin, l’équipe Biomatériaux du Laboratoire de Physique de Clermont (LPC) a récemment mis au point un procédé innovant qui permet la synthèse de matrices tridimensionnelles d’hybrides organique-inorganique à base de verre bioactif et de polymère biocompatible aux caractéristiques variées. Dans la continuité des travaux, il était alors question d’exploiter ce procédé afin de développer un substitut osseux hybride aux propriétés optimisées. Il s’agissait tout d’abord de sélectionner le polymère le plus adéquat pour la régénération osseuse, qui s’est avéré être le polycaprolactone, puis d’optimiser la synthèse (notamment la source de calcium), la structure macroporeuse et la proportion organique-inorganique. Le matériau hybride résultant a ensuite été dopé en éléments thérapeutiques à faible dose (< 5 % de la masse totale) avec des ions strontium ou des nutriments tels que la fisétine et l’hydroxytyrosol qui possèdent un effet ostéogénique. Les mousses hybrides ainsi développées ont finalement été caractérisées in vitro afin de déterminer leurs propriétés physico-chimiques et biologiques, et in vivo afin d’évaluer leur performance. Après 3 mois d’implantation dans un défaut critique de la calvaria de souris, les résultats démontrent le potentiel de ce substitut osseux: comparé au matériau commercial de référence (os bovin traité) qui conduit à une reconstruction osseuse de 16% (± 5%), l’hybride permet une reconstruction allant de 32% (± 3%) lorsqu’il n’est pas dopé, jusqu’à 55% (± 7%) voire 58% (± 7%) lorsqu’il est dopé respectivement en fisétine ou en strontium. Ces travaux de thèse laissent entrevoir des perspectives prometteuses telles que l’association des dopants et l’impression 3D des mousses hybrides polycaprolactone-verre bioactif
The increase in life expectancy results in the decline of seniors’ health conditions and the resurgence of chronic diseases. Among the expressions of senescence, disorders of the musculoskeletal system are particularly disabling and considerably accelerate the state of dependency. This is also the case for young people who suffer from traumatic injuries or pathologic conditions. Thus, about 2.2 million bone grafts are performed worldwide every year. Yet, the level of postoperative complications remains high and is estimated at 15% of surgical operations. These facts outline a major societal concern: animal-based materials present a risk of histocompatibility issues and pathogenicity that may lead to implant failure. This is the reason why research efforts focus on the development of synthetic biomaterials capable of promoting bone regeneration. Currently, commercialised bone substitutes are mainly made of bioactive “ceramics” (calcium phosphates, bioactive glass) that are known to be biocompatible, to spontaneously bond to bone tissues, to promote bone cell adhesion and finally to be bioresorbable. However, despite these remarkable properties, the brittleness of these materials limits their applications. An ingenious solution to this brittleness can be learned from the particular structure of bone tissue. Bone tissue intimately blends an inorganic phase, the bone mineral, which is made of apatite crystals (resorbable calcium phosphates), with an organic phase that is mainly collagen. Such a structure associates the stiffness of the inorganic part with the toughness of collagen fibres. Therefore, in order to obtain implants with mechanical properties similar to that of bone, the strategy consists in combining bioactive ceramics with organic matter. To this end, the Biomatériaux team from the Laboratoire de Physique de Clermont (LPC) recently developed an innovative process that allows the synthesis of tridimensional organic-inorganic hybrids comprised of bioactive glass and biocompatible polymer. The objective of the thesis was to exploit this process in order to develop a hybrid bone substitute with optimal properties. First of all, polycaprolactone was selected as the polymer, especially because of its adequate degradation rate for long-term applications such as bone regeneration. Then, the synthesis process was improved (in particular, the calcium source was changed), the macroporous structure was optimised and the organic-inorganic ratio was chosen. Afterwards, elements that are known to induce an osteogenic effect were incorporated in the hybrid at low doses (< 5% of total weight): an inorganic doping was performed using strontium ions and an organic doping was performed using nutrients such as fisetin or hydroxytyrosol. The resultant hybrid scaffolds were eventually characterised in vitro in order to determine their physicochemical and biological properties and in vivo in order to evaluate their performance. After 3 months of implantation in a mouse calvarial critical defect, results demonstrate the potential of this bone substitute: compared to the reference commercial material (treated bovine bone) that leads to a bone reconstruction of 16% (± 5%), the hybrid allows a reconstruction going from 32% (± 3%) when it is not doped, to 55% (± 7%) and even 58% (± 7%) when it is doped respectively with fisetin or strontium. This thesis paves the way to promising perspectives like the association of doping agents and the 3D printing of polycaprolactone-bioactive glass hybrid scaffolds

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35

Wendling-Hivet, Audrey. "Simulation à l'échelle mésoscopique de la mise en forme de renforts de composites tissés." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0079.

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Анотація:

De nos jours, l’intégration de pièces composites dans les produits intéresse de plus en plus les industriels, particulièrement dans le domaine des transports. En effet, ces matériaux présentent de nombreux avantages, notamment celui de permettre une diminution de la masse des pièces lorsqu’ils sont correctement exploités. Pour concevoir ces pièces, plusieurs procédés peuvent être utilisés, parmi lesquels le RTM (Resin Transfer Molding) qui consiste en la mise en forme d’un renfort sec (préformage) avant une étape d’injection de résine. Cette étude concerne la première étape du procédé RTM, celle de préformage. L’objectif est de mettre en œuvre une stratégie efficace conduisant à la simulation par éléments finis de la mise en forme des renforts à l’échelle mésoscopique. A cette échelle, le renfort fibreux est modélisé par un enchevêtrement de mèches supposées homogènes. Plusieurs étapes sont alors nécessaires et donc étudiées ici pour atteindre cet objectif. La première consiste à créer un modèle géométrique 3D le plus réaliste possible des cellules élémentaires des renforts considérés. Elle est réalisée grâce à la mise en œuvre d’une stratégie itérative basée sur deux propriétés. D’une part, la cohérence, qui permet d’assurer une bonne description du contact entre les mèches, c'est-à-dire, que le modèle ne contient ni vides ni interpénétrations au niveau de la zone de contact. D’autre part, la variation de la forme des sections de la mèche le long de sa trajectoire qui permet de coller au mieux à la géométrie évolutive des mèches dans le renfort. Grâce à ce modèle et à une définition libre par l’utilisateur de l’architecture tissée, un modèle représentatif de tout type de renfort (2D, interlock) peut être obtenu. La seconde étape consiste à créer un maillage hexaédrique 3D cohérant de ces cellules élémentaires. Basé sur la géométrie obtenue à la première étape. L’outil de maillage créé permet de mailler automatiquement tout type de mèche, quelle que soit sa trajectoire et la forme de ses sections. La troisième étape à franchir consiste, à partir du comportement mécanique du matériau constitutif des fibres et de la structure de la mèche, à mettre en place une loi de comportement du matériau homogène équivalent à un matériau fibreux. Basé sur les récents développements expérimentaux et numériques en matière de loi de comportement de structures fibreuses, un nouveau modèle de comportement est présenté et implémenté. Enfin, une étude des différents paramètres intervenant dans les calculs en dynamique explicite est réalisée. Ces deux derniers points permettent à la fois de faire converger rapidement les calculs et de se rapprocher de la réalité de la déformation des renforts. L’ensemble de la chaîne de modélisation/simulation des renforts fibreux à l’échelle mésoscopique ainsi créée est validée par comparaison d’essais numériques et expérimentaux de renforts sous sollicitations simples
Nowadays, manufacturers, especially in transport, are increasingly interested in integrating composite parts into their products. These materials have, indeed, many benefits, among which allowing parts mass reduction when properly operated. In order to manufacture these parts, several methods can be used, including the RTM (Resin Transfer Molding) process which consists in forming a dry reinforcement (preform) before a resin being injected. This study deals with the first stage of the RTM process, which is the preforming step. It aims to implement an efficient strategy leading to the finite element simulation of fibrous reinforcements at mesoscopic scale. At this scale, the fibrous reinforcement is modeled by an interlacement of yarns assumed to be homogeneous and continuous. Several steps are then necessary and therefore considered here to achieve this goal. The first consists in creating a 3D geometrical model of unit cells as realistic as possible. It is achieved through the implementation of an iterative strategy based on two main properties. On the one hand, consistency, which ensures a good description of the contact between the yarns, that is to say, the model does not contain spurious spaces or interpenetrations at the contact area. On the other hand, the variation of the yarn section shape along its trajectory that enables to stick as much as possible to the evolutive shape of the yarn inside the reinforcement. Using this tool and a woven architecture freely implementable by the user, a model representative of any type of reinforcement (2D, interlock) can be obtained. The second step consists in creating a 3D consistent hexahedral mesh of these unit cells. Based on the geometrical model obtained in the first step, the meshing tool enables to mesh any type of yarn, whatever its trajectory or section shape. The third step consists in establishing a constitutive equation of the homogeneous material equivalent to a fibrous material from the mechanical behavior of the constituent material of fibers and the structure of the yarn. Based on recent experimental and numerical developments in the mechanical behavior of fibrous structures, a new constitutive law is presented and implemented. Finally, a study of the different parameters involved in the dynamic/explicit scheme is performed. These last two points allow both to a quick convergence of the calculations and approach the reality of the deformation of reinforcements. The entire chain modeling/simulation of fibrous reinforcements at mesoscopic scale created is validated by numerical and experimental comparison tests of reinforcements under simple loadings

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36

Trnovec, Bystrik. "Experimentelle Untersuchungen zur Schichtbildung im Tiefdruck mittels hydrophobierter Druckform mit Applikationsbeispielen aus dem Bereich der gedruckten OPV." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-209748.

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Die vorliegende Arbeit beschreibt eine experimentelle Untersuchung der Schichtbildung von nichtnewtonschen Flüssigkeiten im Tiefdruckverfahren auf nicht saugfähigen Substraten. Das fluiddynamisch bedingte „viscous fingering“ beim Farbspaltungsprozess soll mittels Hydrophobieren der Druckform gehemmt werden. Ziel ist es, möglichst homogene sowie wellenfreie Schichten zu erzeugen. Um ein direkt miteinander vergleichbares Druckergebnis zu erhalten, wird der Druckstoff parallel mit einer unbehandelten und hydrophobierten Form bedruckt. Als Druckstoff werden anstelle von Druckfarbe funktionale Materialien (vorzugsweise PEDOT:PSS) verwendet und variiert, wobei die elektrischen und geometrischen Schichteigenschaften, beispielsweise der elektrische Widerstand und die Rauheit, zur Ermittlung der gesetzten Ziele untersucht wurden. Hiermit und mittels Nutzung einer hydrophobierten Druckform kann eine deutliche Minderung der Wellenbildung (viscous fingering) bei vielen Druckstoffarten beobachtet werden. Die Minderung des viscous fingering im Farbspaltungsprozess und eine nahezu vollständige Leerung der hydrophobierten Tiefdruckform haben einen wesentlichen Nutzwert für den künftigen Einsatz nicht nur für die „gedruckte Elektronik“
In this work is described experimental research about layer forming from non-Newtonian fluids in gravure printing on non-porous substrates. The viscous fingering, caused through fluid dynamics at splitting of printed material should be decreased by hydrophobic-surface modification of gravure printing form. The aim was to print wave-free homogenous layers. To achieve comparable results, modified and pure form were used simultaneously to print the same material. The printed material was mainly PEDOT:PSS and other, which is used in printed electronics. The properties (surface tension, viscosity) of printed materials were varied by additives. Printing conditions were varied too. The characteristic of printed layers were studied: resistivity, roughness, density, etc. The results shows decreasing of waviness, roughness and viscous fingering in final layer through use of hydrophobic gravure printing form, compared to print results with common printing form. This can be applied not only in the field of printed electronics

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37

Wendling, Audrey. "Simulation à l'échelle mésoscopique de la mise en forme de renforts de composites tissés." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00961196.

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Анотація:

De nos jours, l'intégration de pièces composites dans les produits intéresse de plus en plus les industriels, particulièrement dans le domaine des transports. En effet, ces matériaux présentent de nombreux avantages, notamment celui de permettre une diminution de la masse des pièces lorsqu'ils sont correctement exploités. Pour concevoir ces pièces, plusieurs procédés peuvent être utilisés, parmi lesquels le RTM (Resin Transfer Molding) qui consiste en la mise en forme d'un renfort sec (préformage) avant une étape d'injection de résine. Cette étude concerne la première étape du procédé RTM, celle de préformage. L'objectif est de mettre en œuvre une stratégie efficace conduisant à la simulation par éléments finis de la mise en forme des renforts à l'échelle mésoscopique. A cette échelle, le renfort fibreux est modélisé par un enchevêtrement de mèches supposées homogènes. Plusieurs étapes sont alors nécessaires et donc étudiées ici pour atteindre cet objectif. La première consiste à créer un modèle géométrique 3D le plus réaliste possible des cellules élémentaires des renforts considérés. Elle est réalisée grâce à la mise en œuvre d'une stratégie itérative basée sur deux propriétés. D'une part, la cohérence, qui permet d'assurer une bonne description du contact entre les mèches, c'est-à-dire, que le modèle ne contient ni vides ni interpénétrations au niveau de la zone de contact. D'autre part, la variation de la forme des sections de la mèche le long de sa trajectoire qui permet de coller au mieux à la géométrie évolutive des mèches dans le renfort. Grâce à ce modèle et à une définition libre par l'utilisateur de l'architecture tissée, un modèle représentatif de tout type de renfort (2D, interlock) peut être obtenu. La seconde étape consiste à créer un maillage hexaédrique 3D cohérant de ces cellules élémentaires. Basé sur la géométrie obtenue à la première étape. L'outil de maillage créé permet de mailler automatiquement tout type de mèche, quelle que soit sa trajectoire et la forme de ses sections. La troisième étape à franchir consiste, à partir du comportement mécanique du matériau constitutif des fibres et de la structure de la mèche, à mettre en place une loi de comportement du matériau homogène équivalent à un matériau fibreux. Basé sur les récents développements expérimentaux et numériques en matière de loi de comportement de structures fibreuses, un nouveau modèle de comportement est présenté et implémenté. Enfin, une étude des différents paramètres intervenant dans les calculs en dynamique explicite est réalisée. Ces deux derniers points permettent à la fois de faire converger rapidement les calculs et de se rapprocher de la réalité de la déformation des renforts. L'ensemble de la chaîne de modélisation/simulation des renforts fibreux à l'échelle mésoscopique ainsi créée est validée par comparaison d'essais numériques et expérimentaux de renforts sous sollicitations simples.

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38

Taborda, Sérgio. "Percepção e presença-o corpo na escultura, cinema e biotecnologias." Master's thesis, Instituições portuguesas -- UNL-Universidade Nova de Lisboa -- FCSH-Faculdade de Ciências Sociais e Humanas, 1999. http://dited.bn.pt:80/29026.

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39

Musil, Jiří. "Hledání tvaru skořepinových konstrukcí." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-390254.

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The theme of this doctoral thesis is the design of concrete shell structures with the focus on finding their optimal shape. The optimal shape of a concrete shell is the shape in which for a given load (usually the dead weight of the structure) no significant bending moments are generated in the shell and the structure is in the so-called membrane state. The inspiration for this thesis is the work of Swiss engineer Heinz Isler, who developed the shapes of shell structures using model tests of appropriately loaded flexible membranes. He developed the shell structure for large spans by inverting the resultant shape, which carried its weight almost entirely via membrane forces. The numerical solution of the above experiments using Midas Civil is presented herein. The basic principles of the method are demonstrated on the example of sagged cable. The numerically found shapes are compared with the analytical solution. A shell is designed based on the numerically found shapes and its stress response to dead load is described, particularly in relation to the membrane action. In the next part, the acquired knowledge and methods were used to design three relatively complicated shell structures. Each structure was statically analysed and its static behaviour was described. Structures with perfectly rigid or flexible supports, which simulate real behaviour of the supports, were studied. In the final phase, the results of static analysis of the selected shell were experimentally verified on a physical model in a scale of 1: 55.56. The model has been built using 3D printing. The thesis describes the use of a modelling similarity, the model design, the production process, and the experiment. The load test confirmed the optimal design of the shell structure and the validity of the numerical method for finding their shapes.

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40

Guesnet, Laura. "Développement de nouvelles architectures de piles à combustible SOFC tout cérine pour un fonctionnement à température réduite." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0218.

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En employant de nouvelles architectures de cellules à oxyde solide (SOC - Solid Oxide Cells), il est possible d’en réduire la température de fonctionnement. L’objectif de cette thèse a donc été d’élaborer des mises en forme innovantes afin de diminuer le nombre d’étapes nécessaires à la fabrication de la cellule, permettant aussi d’en diminuer le coût : l’élaboration d’un support poreux/dense/poreux tout coulage en bande puis infiltration de catalyseurs pour l’obtention des électrodes est le procédé retenu. Le support poreux/dense/poreux a été exclusivement préparé à base de GDC10 (Ce0,9Gd0,1O2-δ) pour éviter les problèmes de réactivité entre les différentes couches. Au cours de cette thèse, deux méthodes de mises en forme ont été utilisées successivement: pressage/sérigraphie/infiltration (1) puis coulage en bande/infiltration (2). Dans chacun des cas, les paramètres de mises en forme ont été optimisés dans le but d’obtenir les meilleures performances électrochimiques. La méthode de mise à forme (1) a déjà fait l’objet d’une partie de thèse à l’ICMCB côté oxygène, mais elle a été perfectionnée côté hydrogène : couche de collectage, nature du catalyseur (NiO, CuO, cérine dopée yttrium), taux d’infiltration. Pour diminuer le nombre de cycles nécessaires et améliorer la qualité de l’imprégnation, une nouvelle technique a été employée : l’infiltration par voie supercritique. Dans le cas de la mise en forme (2), les paramètres propres à l’élaboration de la suspension (nature des additifs, nature des billes/jarre employées) et à celle des supports poreux/dense/poreux (cycles de déliantage/frittage) ont permis d’obtenir des résistances de polarisation très proches de celles obtenues grâce à la mise en forme (1), en dépit de résistances séries encore élevées sans doute en lien avec de pollutions résiduelles carbonées. Les paramètres finalement retenus sont : un dispersant de type ester phosphorique, 90% de graphite ajouté pour réaliser les squelettes poreux, un déliantage conduit à 800°C/6h sous O2 humide, et un frittage de l’ensemble à 1450°C/3h
When involving new solid oxide cells (SOCs) architectures, it’s possible to reduce their operating temperature. The objective of this thesis was therefore to develop innovative shaping processes in order to reduce the cell manufacturing steps number, also allowing to reduce their cost : the preparation of a porous/dense/porous support by tape-casting, then the infiltration of catalysts to obtain the electrodes was the chosen process. The porous/dense/porous support was only prepared with GDC10 (Ce0.9Gd0.1O2-δ) to avoid chemical reactivity issues between the various layers. During this thesis, two shaping methods were successively used: pressing/screen-printing/infiltration (1) then tape-casting/infiltration (2). In each case, the shaping parameters have been optimized in order to obtain the best electrochemical performances. The shaping method (1) was already part of a thesis topic at ICMCB regarding the oxygen side of the SOC, but it has been here improved regardin the hydrogen side: the collecting layer, the catalyst nature (NiO, CuO, yttrium doped ceria), infiltration rate. To reduce the number of required cycles and improve the impregnation quality, a new technique was used: the infiltration in supercritical medium. In the case of shaping (2), the specific parameters of the i) suspension preparation (additives nature, nature of the used balls/jar) and of the ii) porous/dense/ porous supports (debinding/sintering cycles) have made it possible to obtain polarization resistances very close to those obtained by shaping (1), despite slightly higher series resistances, probably in linkto some remaining carbon pollution. The parameters finally retained are: a phosphoric ester type dispersant, 90% of graphite added to shape the porous skeletons, a debinding performed at 800°C/6h under wet O2, and a whole sintering at 1450°C/3h

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41

Hu, Xusheng. "Study of the Thermal Performance of Metal Foam and PCM Composite for Thermal Energy Storage." Thesis, Troyes, 2021. http://www.theses.fr/2021TROY0003.

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Le but de cette thèse est d'étudier les performances thermiques d'une mousse métallique ainsi que de ses composites avec un matériau à changement de phase (MCP) en utilisant des méthodes expérimentales et numériques. La mousse métallique étudiée possède une structure cellulaire cubique. Les effets des conditions de contact et de chaleur sur le taux de stockage de chaleur dans le composite MCP sont d’abord simulés numériquement. Ensuite, la mousse métallique avec une structure cellulaire cubique est conçue et fabriquée par impression 3D. L'étude expérimentale permet par la suite d’observer l'évolution de la fusion du MCP introduit dans la mousse métallique. Parallèlement, une méthode numérique à l'échelle des pores est utilisée pour simuler les caractéristiques de transfert thermique dans le composite MCP. Il ressort des résultats que la mousse métallique d'enrobage peut réduire le temps total de fusion du matériau MCP. Compte tenu de l'influence des paramètres de morphologie de la mousse métallique, nous avons étudié numériquement le comportement thermique de la mousse métallique en variant la porosité et la densité de pores. La dernière partie de cette thèse consiste à explorer une application de la mousse métallique dans les dissipateurs thermiques à base de MCP. Les essais expérimentaux sur composite MCP permettent d’obtenir la réponse thermique des dissipateurs thermiques. Les effets de la porosité de la mousse métallique et de la puissance du chauffage sur la réponse thermique du dissipateur thermique sont également mis en évidence
The aim of this Ph.D. thesis is to study the thermal performance of metal foam and phase change material (PCM) composite by using the experimental and numerical methods, in which metal foam possesses a cubic cell structure and is fabricated by 3D printing technique. Firstly, the effects of contact and heat conditions on heat storage rate of PCM composite are investigated to provide theoretical guidance for the practical application of PCM composite in thermal energy storage (TES) system. Then the metal foam with a cubic cell structure is designed and fabricated by 3D printing. The experimental investigation is carried out to examine the melting evolution of PCM embedded in metal foam. Meanwhile, the pore-scale numerical method is also proposed and used to investigate heat transfer characteristics of PCM composite. It is found from the results that the embedding metal foam can short the total melting time of PCM. Considering the influence of morphology parameters of metal foam, the thermal behavior of metal foam with different porosities and pore densities is numerically studied. The last part of this thesis explores the application of metal foam in PCM based heat sink. The thermal response of heat sinks using PCM composite is obtained by the experimental test, including base temperature, temperature variation, operating time and enhancement ratio of operating time. Also, the effects of the porosity of metal foam and the power level of the heater on the thermal response of heat sink are investigated

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42

Barajas, Leandro G. "Process Control in High-Noise Environments Using A Limited Number Of Measurements." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/7741.

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The topic of this dissertation is the derivation, development, and evaluation of novel hybrid algorithms for process control that use a limited number of measurements and that are suitable to operate in the presence of large amounts of process noise. As an initial step, affine and neural network statistical process models are developed in order to simulate the steady-state system behavior. Such models are vitally important in the evaluation, testing, and improvement of all other process controllers referred to in this work. Afterwards, fuzzy logic controller rules are assimilated into a mathematical characterization of a model that includes the modes and mode transition rules that define a hybrid hierarchical process control. The main processing entity in such framework is a closed-loop control algorithm that performs global and then local optimizations in order to asymptotically reach minimum bias error; this is done while requiring a minimum number of iterations in order to promptly reach a desired operational window. The results of this research are applied to surface mount technology manufacturing-lines yield optimization. This work achieves a practical degree of control over the solder-paste volume deposition in the Stencil Printing Process (SPP). Results show that it is possible to change the operating point of the process by modifying certain machine parameters and even compensate for the difference in height due to change in print direction.

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43

CHANG, YIN CHING, and 殷慶璋. "The Study of the Impact of Computer Forms Printing Industry as Computer Technology Changes." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/73512213783638724683.

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碩士
中國文化大學
印刷傳播研究所
88
The purpose of this research is to discuss the impact of computer forms printing industry as computer technology changes. The basic frame of this research is from the theory of Martin Dehayes, Hofferand Perkins (1991), and the professor and industry expert modification. The research object is investigated and based on members of Computer Forms Printing Member and Factory Register (1999) which is subsidiary to Taiwan Printing Industry Association. The method of this investigation is universal and general. Here is conclusion: 1.The result of this thesis show that New Technology includes the progress and vast using of printers and environment of Office Automation is getting mature, and the replacement of information product are also big push are affecting factories such as general computer forms ones, computer color forms ones, and exceptional computer forms ones more signally; New Technology includes the depending on less quantity but various type consumption methods, replacement of information product, and increasing demand of professional computer software are affecting the factories such as general computer forms ones, computer color forms ones, and exceptional computer forms ones more signally. 2.Three factors are affecting the computer forms printing industry as this report suggests. The first factor is the New Technology factor. It includes the environment of Office Automation is getting mature and the increasing demand of professional computer software. Furthermore, the electronic commercial and Internet technology, replacement of information product are also big push. The second factor is technology of production of computer forms, which contains the competition of industry, investment of computer printing equipment, automation of production of computer forms, and education of Hi-tech technology. The third factor is the new type of consumption, which is depended on less quantity but various type consumption methods. 3.As shown in this research, the information technology changing, which related to computer forms printing industry, evidently depends on personal opinion. 4.According to the research, the various type of computer forms printing industry products and factories such as general computer forms ones, computer color forms ones, and exceptional computer forms ones are affecting the technology apparently differently.

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44

Robles-Martinez, P., X. Xu, S. J. Trenfield, A. Awad, A. Goyanes, Richard Telford, A. W. Basit, and S. Gaisford. "3D Printing of a Multi-Layered Polypill Containing Six Drugs Using a Novel Stereolithographic Method." 2019. http://hdl.handle.net/10454/17370.

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Yes
Three-dimensional printing (3DP) has demonstrated great potential for multi-material fabrication because of its capability for printing bespoke and spatially separated material conformations. Such a concept could revolutionise the pharmaceutical industry, enabling the production of personalised, multi-layered drug products on demand. Here, we developed a novel stereolithographic (SLA) 3D printing method that, for the first time, can be used to fabricate multi-layer constructs (polypills) with variable drug content and/or shape. Using this technique, six drugs, including paracetamol, cffeine, naproxen, chloramphenicol, prednisolone and aspirin, were printed with dfferent geometries and material compositions. Drug distribution was visualised using Raman microscopy, which showed that whilst separate layers were successfully printed, several of the drugs diffused across the layers depending on their amorphous or crystalline phase. The printed constructs demonstrated excellent physical properties and the different material inclusions enabled distinct drug release profiles of the six actives within dissolution tests. For the first time, this paper demonstrates the feasibility of SLA printing as an innovative platform for multi-drug therapy production, facilitating a new era of personalised polypills.

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45

Wang, Shang-Tong, and 王上通. "Improving Form-Printing Software Maintenance by Maintenance-Oriented Design." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/85022192903962741134.

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Анотація:

碩士
國立中興大學
資訊網路多媒體研究所
100
Software maintenance cost has always accounted for a large share of total software cost. Study has shown that optimizing software maintenance should begin at the software planning phrase by evaluating the software maintenance problems. The main goal is to improve software maintainability and to reduce the probability of maintenance requirements. Yet most mathematic researches in the past had focused on managing software maintenance after its occurrence. The tasks associated with software maintenance can be divided into corrective maintenance caused by errors in software construction, or adaptive and comprehensive maintenance needed for software that can yet accommodate future technical requirements. Errors in software construction can be effectively corrected via software engineering; it is the insufficient software adaptability that requires the most maintenance, and there is a lack of research and useable techniques associated with this problem. The purpose of maintenance-oriented design is to reduce the occurrence of software maintenance to optimize the goal of software maintenance engineering. User experiences are analyzed to offset the inability to identify every possible demand by the users. Software maintenance occurrences are reduced and means of resolving the problems are provided based on sample occurrences that have occurred. The common mandatory basic functions are then selected and pre-established in the software system to strengthen software adaptability. Information and software structures are then generically designed so that information processing signs and functions are separately composed. This way it would be easier to maintain software structure, information processing can be generically designed, and users would be allowed to customize the user interface for information processing. Customization can better satisfy user need, and these methods will help reduce the occurrence of software maintenance. This study utilized maintenance-oriented design and tested using generic form-printing software. The result showed that generically designed form-printing software can process the items to be printed without constraints, and would only require software maintenance when information processing ability is sufficient for unknown form formats, as new capability would have to be added to process that information. This type of design can reduce both the probability and cost of software maintenance.

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46

Nascimento, Nuno Alexandre Mota Ferreira Pereira. "Numerical and Experimental Analysis of Polymeric Foams obtained by 3D Printing (Additive Manufacturing)." Master's thesis, 2019. https://hdl.handle.net/10216/122455.

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47

Abd, El Kader Magdy Ezzat. "Application of Hot-Melt Ink Jet Processes for Imaging at Offset Printing Form Cylinder." Doctoral thesis, 2003. https://monarch.qucosa.de/id/qucosa%3A18099.

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The present work related to apply hot-melt ink-jet process for imaging at offset lithographic printing form, to utilise a reusable surface for many times and particularly related to validating thermal and ultrasonic erasing processes. This dissertation investigated systematically the role of certain factors towards affecting erasing image area process on print surfaces. Thermal erasing process approved to melt and suck the image area from the surface, the results were adopted by using contact angle measurements and scanning electron microscope. Ultrasonic erasing process permitted to solve the image area by choosing erasing chemistries, influence of selected erasing chemistries on printing surface, and evaluation the process, the results were tested by UV/Vis spectrometer, contact angle, profileometery and visual microscope.
Der Fortschritt im Bereich von Charakterisierung und Verständnis für Hot-melt Ink Jet Prozesse zur Bebilderung von Offsetdruckform-Zylindern ist ein Ergebnis dieser Forschung. Die Systematik dieser Arbeit basiert auf einem theoretischen Teil, um einen geeigneten Löschprozess auszuwählen. Der Löschprozess hängt von den Eigenschaften des Hot-melt Ink Jet Materials und der genutzten Aluminiumdruckoberfläche ab. Diese werden systematisch im Labormaßstab experimentell untersucht. Der thermische Prozess wurde einerseits durch Benetzbarkeitsprüfungen und anderseites durch Rasterelektronmikroskopaufnahmen bewertet.Der Ultraschallprozess ist ein nasser Löschprozess. Die Untersuchungen wurden in vier Stufen systematisch durchgeführt - Auswahl vom geeigneten Lösungsmitteln - Einflüsse von ausgewählten Lösungsmitteln auf nicht beschichtete und beschichtete Aluminium platten - Evaluation eines Ultraschalllöschprozesses - Validation eines Löschprozesses; zur Bewertung des Löschprozesses wurden mehrere Druckplattenproben bebildert und gelöscht Die Ergebnisse wurden durch UV/Vis Spektrometer, Kontaktwinkel, Profiliometrie und Visuelle Mikroskopie getestet.

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48

Oliveira, Rúben Miguel Cardoso Gomes. "Impressão 3D de polímeros: Influência do fator de forma na avaliação das propriedades mecânicas." Master's thesis, 2019. http://hdl.handle.net/10316/98256.

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Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia
A impressão 3D de polímeros passou da prototipagem rápida para o fabrico de componentes/peças com aplicações em áreas distintas que vão desde a saúde até à aeronáutica. A possibilidade de efetuar peças com baixo custo, personalizadas e com menor impacto ambiental estão entre os fatores que impulsionaram a popularização deste método de processamento.No entanto, vários são os fatores de processamento durante a impressão 3D que podem influenciar as propriedades mecânicas das peças produzidas. De entre eles, o fator forma, que se refere ao conjunto dos limites exteriores de um corpo que lhe conferem determinada configuração, nunca foi estudado, pelo menos de acordo com a bibliografia consultada.Assim, o objetivo deste trabalho é o de avaliar o fator forma nas propriedades mecânicas de poli( -caprolactona) (PCL) após impressão 3D. Para o efeito foram produzidos provetes com geometria paralelepipédica e tubular, por impressão longitudinal e em altura (transversal). Devida à grande utilização deste polímero em diversos dispositivos médicos, foi também avaliada a influência do envelhecimento em soro fisiológico nas mesmas propriedades mecânicas.Este estudo permitiu concluir que as melhores propriedades mecânicas são obtidas para a geometria de paralelepípedo com uma impressão longitudinal e que o envelhecimento em soro fisiológico influência de modo negativo todas as propriedades avaliadas ao longo deste estudo .
3D printing of polymers has evolved from rapid prototyping to component/part manufacturing with applications in distinct areas ranging from health to aeronautics. The possibility of making low-cost, customized parts with less environmental impact are among the factors that have led to the exponential growth of this processing method.However, there are several processing factors during 3D printing that can influence the mechanical properties of the parts produced. Among them, the form factor, which refers to the set of outer limits of a body that give it a certain configuration, has never been studied, at least according to the bibliography consulted.Thus, the objective of this work is to evaluate the shape factor in the mechanical properties of poly (-caprolactone) (PCL) after 3D printing. For this purpose, specimens with parallelepiped and tubular geometry were produced by longitudinal and height (transversal) impressions. Due to the great use of this polymer in several medical devices, the influence of aging in physiological saline solution on the same mechanical properties was also evaluated.This study allowed to conclude that the best mechanical properties are obtained for parallelepiped geometry with a longitudinal impression and that aging in physiological saline negatively influences all the properties evaluated throughout this study .

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49

Dias, Adriana Maria Lopes. "Impressão FFF de polímeros de memória de forma." Master's thesis, 2020. http://hdl.handle.net/1822/70524.

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Анотація:

Dissertação de mestrado em Engenharia de Polímeros
Os shape-memory polymers (SMP), ou polímeros de memória de forma, são uma classe de materiais inteligentes, mecanicamente ativos, capazes de alterar a sua forma em resposta a um estímulo, como por exemplo, temperatura, radiação, impulsos elétricos, etc. Nesta dissertação de mestrado pretendeu-se avaliar as características de um material com memória de forma, impresso pela técnica de Fabricação por Filamento Fundido (FFF). Para o efeito, foi necessário definir e validar uma metodologia adequada à caracterização do mesmo, tendo como principais objetivos analisar a influência da temperatura de recuperação e influência da espessura da amostra na força que o material promove durante a fase de recuperação. Numa fase inicial, foi extrudido filamento do material SMP com diâmetro calibrado para o processo de impressão 3D. Foi também necessário selecionar a geometria da amostra para o ensaio e proceder à identificação da janela operatória de impressão deste material. Imprimiram-se várias peças com diferentes espessuras (0.5, 1 e 2mm), para analisar a sua influência sobre a força de recuperação e caraterizaram-se as amostras de acordo com a metodologia definida usando o equipamento de análise mecânica dinâmica (DMA), que analisou a recuperação restringida do material. Para uma mesma espessura, 1 mm, obteve-se, para a temperatura mínima de 50 °C, a força de recuperação de 104 mN e, para a temperatura máxima de 70 °C, obteve-se a força de recuperação de 494 mN; uma variação de 20 °C na temperatura originou um aumento de 390mN (375 %) na referida força. Para uma mesma temperatura, 70 °C, obteve-se, para a espessura mínima de 0.5mm, a força de recuperação de 325 mN e, para a espessura máxima de 2mm, obteve-se a força de recuperação de 932 mN; um aumento de 1.5 mm na espessura provocou um aumento de 607 mN (187 %) na força de recuperação. Concluiu-se assim que, quanto mais elevada for a temperatura de recuperação, maior é o valor da força que o material promove quando recupera a forma permanente e que, quanto maior a espessura do provete, maior o valor desta força.
Shape memory polymers (SMP) are a class of mechanically active smart materials, capable of altering their shape in response to a stimulus as, temperature, radiation, electrical impulses, etc. In this master's dissertation, it was intended to evaluate the shape memory characteristics of a material, via samples printed by the Fused Filament Fabrication (FFF) technique. For this purpose, it was necessary to define and to validate an appropriate methodology, with the main objective of analyzing the influence of the recovery temperature and of the thicknesses of the samples on the force released during the recovery stage. In an initial phase, a calibrated diameter SMP material filament for the 3D printing process was extruded. It was also necessary to select the geometry of the test specimen, and proceed to the identification of the operating window for printing this material. Several samples were printed with different thicknesses (0.5, 1 e 2 mm), in order to also analyze their influence on the recovery force. These components were then characterized according to a methodology using the dynamic mechanical analysis equipment (DMA), which analyzed the constrained recovery of the material. For the 1 mm samples thickness, and for the minimum recovery temperature of 50 °C, a recovery force of 104 mN was obtained, while for the maximum temperature of 70 °C this force was 494 mN. Therefore, a 20 °C variation in temperature caused an increase of 390 mN (375 %) in that force. For the 70 °C recovery temperature, and the maximum thickness of 2 mm, a recovery force of 932 mN was obtained, i.e.an increase of 1.5 mm in thickness caused an increase of 607 mN (187 %) in the recovery force. It was concluded that, the higher the recovery temperature, the higher the value of the recovery force and that the higher the thickness of the sample, the higher the value of this force.

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50

Abd-el-Kader, Magdy Ezzat [Verfasser]. "Application of hot melt ink jet processes for imaging at offset printing form cylinder / vorgelegt von Magdy Ezzat Abd El Kader." 2004. http://d-nb.info/970645775/34.

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