Articles de revues : « Shape replica process »

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Park, Tae Wan, et Woon Ik Park. « Pattern Transfer Printing by Controlling the Deposition Angle to Form Various Patterns ». Korean Journal of Metals and Materials 58, n^o 2 (5 février 2020) : 145–50. http://dx.doi.org/10.3365/kjmm.2020.58.2.145.

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The nanofabrication of modern electronic devices requires advanced nanopatterning technologies. To fabricate desirable nanodevices with excellent device performance, controlling the shape and dimension of the pattern is very important. However, to achieve more facile and faster device fabrication, with better pattern resolution, pattern-tunability, process simplicity, and cost-effectiveness, some remaining challenges still need to be resolved. In this study, we introduce a simple and practical method to generate various patterns using a nanotransfer printing (nTP) process. To obtain functional materials with diverse shapes on a polymer replica pattern, in the nTP process we controlled the angle of deposition before transfer-printing. First, we obtained three different pattern shapes with a thickness of ~ 30 nm on polymethyl methacrylate (PMMA) replica patterns. Then, the deposited functional patterns on the PMMA patterns are successfully transfer-printed onto SiO2/Si substrates, showing line, L-shape line, and concavo-convex patterns. We observed the pattern shapes of the patterns by scanning electron microscope (SEM) and optical microscope. Moreover, we systemically analyzed how to form patterns of various shapes using one kind of master mold. We expect that this simple approach will be widely used to fabricate various useful patterns for electronic device applications.

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Andriani, Claudy, Wahyu Caesarendra, Tegoeh Tjahjowidodo, Tomi Wijaya et Bobby K. Pappachan. « Modal Analysis of Replica Boss Hole During the Deburring Process in Aerospace Manufacturing Industry ». MATEC Web of Conferences 159 (2018) : 02035. http://dx.doi.org/10.1051/matecconf/201815902035.

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The monitoring of surface finishing processes in aerospace manufacturing industry becomes one of key issues to maintain the overall quality of product or part. To date, the surface quality monitoring post machining processes such as deburring, use visual inspection, surface roughness test or laser gap gun. The whole manufacturing process then requires a considerable amount of time as the production line must be halted due to these measurements taking place. This study presents an online monitoring system to measure the chamfer quality of replica boss hole post-deburring process. Vibration signal was measured during the deburring process and the features that correlate to the deburring stages (passes) were extracted. This paper focuses on the validation of actual vibration signal with the modal analysis of work coupon (replica boss hole) to obtain the correlation between the vibration amplitude level on particular region and the mode shape of work coupon during the deburring process.

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Nakamura, Fumi, Kenta Suzuki, Akihiro Noriki et Takeru Amano. « Micromirror fabrication for co-packaged optics using 3D nanoimprint technology ». Journal of Vacuum Science & ; Technology B 40, n^o 6 (décembre 2022) : 063203. http://dx.doi.org/10.1116/6.0002119.

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Co-packaged optics (CPO) is a key technology for addressing power bottlenecks in datacenters by integrating optical and electrical components and replacing electrical wiring with optical links. In the CPO module where silicon chips are embedded on the substrate and polymer waveguides are integrated as optical connections, a pair of 3D micromirrors can achieve low-loss and wideband optical coupling from silicon photonics to polymer waveguides. The shape of the polymer micromirror patterned by grayscale photo lithography depends on process conditions and requires high fabrication accuracy. In this study, photonanoimprint technology is adopted for stable micromirror fabrication. The imprint process for a polymer micromirror was considered from a hyperelastic analysis using the finite element method. The master mold was prepared using grayscale lithography with photosensitive polyimide as a template of a polydimethylsiloxane (PDMS) replica mold. The micromirror fabrication was demonstrated on a 4-in. silicon wafer. By imprinting into a guide groove structure with a PDMS replica mold, over 30 μm-height micromirrors were stably obtained multiple times by a step-and-repeat imprint. The linear part of the patterned mirror by the imprint process was more than 23.5 μm for four times imprinting, and the fabricated mirror shape was improved compared with grayscale lithography. The total height misalignment is 5 μm for 12 mirrors in four imprints, and 70% coupling efficiency in calculation was achieved.

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Kim, Young Ho, Jeong Woo Sohn, Youngjae Woo, Joo Hyun Hong et Juyoung Park. « Fabrication of PEG Hydrogel and PDMS Microstructures by a Simple UV Curing Process for Nanobio-Chip Applications ». Advanced Materials Research 941-944 (juin 2014) : 404–10. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.404.

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Polyethylene glycol (PEG) hydrogel microstructures with various shapes and sizes on a glass chip were prepared by a simple and rapid ultraviolet (UV) irradiation method using a metal mask. Photocurable PEG solution prepared by mixing 95 wt.% polyethylene glycol diacrylate and 5 wt.% 2-hydroxy-2-methylpropiophenone as a photo-initiator was injected to the gap between bottom and upper glasses in a simply assembled glass chip. After a metal mask with line-and-space or complex patterns was placed on the glass chip, UV light from a spot UV irradiation device was exposed to the glass chip through the metal mask for 7 seconds at UV intensity of 26 mW/cm2. Then the PEG hydrogel micropatterns on the glass chip were obtained after removing unreacted PEG solution by air blowing. To prepare more rigid microstructure, the prepared PEG micropatterned chip was exposed under UV light for 20 seconds. Then the PEG hydrogel micropattern chip was fabricated by a simple and rapid procedure. Micropattern transferring was performed from the PEG hydrogel chip to polydimethyl siloxane (PDMS) replica by a solution casting. The prepared micropatterned PDMS replicas showed similar shape and size of microstructures compared to that of the corresponded PEG hydrogel chip. Thus the PEG hydrogel microstructures on a glass chip could be used as a mold to fabricate micropattern PDMS chips for nanobio-chip applications. Furthermore, the present method provides large scale chip fabrication, more than 4 cm-length and 4 cm-width in a single step, not only PEG hydrogel chips but also PDMS chips.

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Kwon, Hyuk-Jun, Junyeob Yeo, Jae Jang, Costas Grigoropoulos et Jae-Hyuck Yoo. « Single Pass Laser Process for Super-Hydrophobic Flexible Surfaces with Micro/Nano Hierarchical Structures ». Materials 11, n^o 7 (17 juillet 2018) : 1226. http://dx.doi.org/10.3390/ma11071226.

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Wetting has been studied in various fields: chemical industry, automobile manufacturing, food companies, and even life sciences. In these studies, super-hydrophobic surfaces have been achieved through complex steps and processes. To realize super-hydrophobicity, however, we demonstrated a simple and single pass laser process for the fabrication of micro/nano hierarchical structures on the flexible polytetrafluoroethylene (PTFE, Teflon) surface. The fabricated hierarchical structures helped increase the hydrophobicity by augmenting the surface roughness and promoting air-trapping. In addition, we employed a low-cost and high-throughput replication process producing numerous polydimethylsiloxane (PDMS) replicas from the laser-processed PTFE film. Thanks to the anti-adhesive characteristics of PTFE and the elasticity of PDMS, the structure perfectly transferred to the replica without any mechanical failure. Moreover, our designed mesh patterns offered the possibility of large area applications through varying the process parameters (pitch, beam spot size, laser fluence, and scan speed). Even though mesh patterns had relatively large pitch (190 μm), we were able to achieve high contact angle (>150°). Through pneumatically deformed structure, we clearly showed that the shape of the droplets on our laser-processed super-hydrophobic surface was spherical. Based on these outcomes, we can expect our single laser pulse exposure process can overcome many drawbacks and offer opportunities for advancing applications of the wetting phenomena.

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Saadat, Mozafar, Marie Taylor, Arran Hughes et Amir M. Hajiyavand. « Rapid prototyping method for 3D PDMS microfluidic devices using a red femtosecond laser ». Advances in Mechanical Engineering 12, n^o 12 (décembre 2020) : 168781402098271. http://dx.doi.org/10.1177/1687814020982713.

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A rapid prototyping technique is demonstrated which uses a red femtosecond laser to produce a metallic mould which is then directly used for the replica moulding of PDMS. The manufacturing process can be completed in less than 6 h making it a viable technique for testing new designs quickly. The technique is validated by creating a microfluidic device with channels of height and depth of 300 µm, with a ramp test structure where the height and width of the channels reduces to 100 µm to demonstrate the techniques 3D capabilities. The resulting PDMS device was easily removed from the metallic mould and closely replicated the shape aside the expected shrinkage during thermal curing. As the technique uses a single replica process, the surface roughness at the base of the channels corresponds to the un-ablated polished metal mould, resulting in a very low surface roughness of 0.361 nm. The ablated metallic mould surface corresponds to the top of the PDMS device, which is bonded to glass and does not affect the flow within the channels, reducing the need for optimisation of laser parameters. Finally, the device is validated by demonstrating laminar flow with the no-slip condition.

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El Chawich, Ghenwa, Joelle El Hayek, Vincent Rouessac, Didier Cot, Bertrand Rebière, Roland Habchi, Hélène Garay et al. « Design and Manufacturing of Si-Based Non-Oxide Cellular Ceramic Structures through Indirect 3D Printing ». Materials 15, n^o 2 (8 janvier 2022) : 471. http://dx.doi.org/10.3390/ma15020471.

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Additive manufacturing of Polymer-Derived Ceramics (PDCs) is regarded as a disruptive fabrication process that includes several technologies such as light curing and ink writing. However, 3D printing based on material extrusion is still not fully explored. Here, an indirect 3D printing approach combining Fused Deposition Modeling (FDM) and replica process is demonstrated as a simple and low-cost approach to deliver complex near-net-shaped cellular Si-based non-oxide ceramic architectures while preserving the structure. 3D-Printed honeycomb polylactic acid (PLA) lattices were dip-coated with two preceramic polymers (polyvinylsilazane and allylhydridopolycarbosilane) and then converted by pyrolysis respectively into SiCN and SiC ceramics. All the steps of the process (printing resolution and surface finishing, cross-linking, dip-coating, drying and pyrolysis) were optimized and controlled. Despite some internal and surface defects observed by topography, 3D-printed materials exhibited a retention of the highly porous honeycomb shape after pyrolysis. Weight loss, volume shrinkage, roughness and microstructural evolution with high annealing temperatures are discussed. Our results show that the sacrificial mold-assisted 3D printing is a suitable rapid approach for producing customizable lightweight highly stable Si-based 3D non-oxide ceramics.

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Krumpen, Stefan, Reinhard Klein et Michael Weinmann. « Towards Tangible Cultural Heritage Experiences—Enriching VR-based Object Inspection with Haptic Feedback ». Journal on Computing and Cultural Heritage 15, n^o 1 (28 février 2022) : 1–17. http://dx.doi.org/10.1145/3470470.

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VR/AR technology is a key enabler for new ways of immersively experiencing cultural heritage artifacts based on their virtual counterparts obtained from a digitization process. In this article, we focus on enriching VR-based object inspection by additional haptic feedback, thereby creating tangible cultural heritage experiences. For this purpose, we present an approach for interactive and collaborative VR-based object inspection and annotation. Our system supports high-quality 3D models with accurate reflectance characteristics while additionally providing haptic feedback regarding shape features of the object based on a 3D printed replica. The digital object model in terms of a printable representation of the geometry as well as reflectance characteristics are stored in a compact and streamable representation on a central server, which streams the data to remotely connected users/clients. The latter can jointly perform an interactive inspection of the object in VR with additional haptic feedback through the 3D printed replica. Evaluations regarding system performance, visual quality of the considered models, as well as insights from a user study indicate an improved interaction, assessment, and experience of the considered objects.

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Lim, Soon Hyuk, Nguyễn Hoàng Ly, Jung A. Lee, Ji Eun Kim, Se-Woong La, Vu Thi Huong, Thi-Giang Tran et al. « Nanopatterned Polymer Molds Using Anodized Aluminum Templates for Anti-Reflective Coatings ». Polymers 13, n^o 19 (29 septembre 2021) : 3333. http://dx.doi.org/10.3390/polym13193333.

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This work introduces a facile geometry-controlled method for the fabrication of embossed and engraved polymeric moth-eye-inspired nanostructures in imprinting molds using anodic aluminum oxide (AAO) templates, resulting in a novel anti-reflective transparent coating. The moth-eye nanostructures are prepared directly on the surface of a flexible polyethylene terephthalate (PET) substrate. As a prerequisite procedure, a UV-curable polyurethane acrylate resin is spun on the PET. The shape of the moth-eye nanostructures can then be adjusted by controlling the size and shape of the nanopores in the AAO templates. Both embossed and concaved polymer moth-eye nanostructures were successfully mounted on a PET substrate. Embossed polymer replica molds were prepared using the AAO master templates in combination with an imprinting process. As revealed by field-emission electron microscope (FE-SEM) images, conical nanopatterns in the AAO template with a diameter of ~90 nm and a depth of ~100 nm, create a homogeneous embossed morphology in the polymer moth-eye nanostructure. The polymeric molds with the depths of 300 and 500 nm revealed the amalgamated structures in their apexes. In addition, a dip-imprinting process of the polymeric layers was implemented to yield a concaved mold by assembly on the surface of the 100 nm embossed polymer mold substrate. Considering that the embossed structures may be crumbled due to their protuberant shapes, the concaved geometries can have an advantage of stability in a certain application concerning physical degradation along with a higher transmission by ~2%, despite somewhat nonuniform structure. The experimental and theoretical results of this study indicate that this polymer layer has the potential for use in anti-reflective coating applications in transparent films.

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Bae, Eun-Jeong, Hyeong-Kyu Maeng, Ji-Soo Shin, Dong-Wook Park, Young-Wook Park et Dong-Hyun Baek. « Micro-Sphere PDMS for Enhancing Light Extraction in Organic Light-Emitting Devices ». Nanomaterials 12, n^o 12 (10 juin 2022) : 2007. http://dx.doi.org/10.3390/nano12122007.

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We present a micro-sphere PDMS film to improve the external quantum efficiency (EQE) in OLEDs. The micro-sphere PDMS film was fabricated with the breath figure (BF) and replica molding process. The polymer template was prepared through stabilization of the water droplets at the polymer/water interface. The micro-sphere PDMS film was fabricated by pouring PDMS on the polymer template. At a 45 mg/mL concentration, the size of the spheres was approximately 12.3 µm and they had the most circular shape, so this condition yielded the best performance, with an improvement of 33% in the EQE and the widest viewing angle ranging from 0° to 50°. As a result, the sphere film’s size and distribution seem to play important roles in enhancing the EQE in OLEDs. Furthermore, the flexible sphere film based on polymeric materials could offer an effective, large-scale, mass-produced product and a simple process and approach to achieve high efficiency in flexible OLEDs.

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Moskvin, Aleksei, Mariia Moskvina et Victor Kuzmichev. « Parametric modeling of historical mannequins ». International Journal of Clothing Science and Technology 32, n^o 3 (24 décembre 2019) : 366–89. http://dx.doi.org/10.1108/ijcst-06-2019-0093.

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Purpose Digital technologies are widely used for digitization of museum and archival heritage and creation of digital, multimedia and online exhibitions, especially in terms of costume history. Digital exhibitions require historical dress forms which were used in the past for costume presentation. The purpose of this paper is to develop a new method for parametric modeling of the nineteenth century dress forms in accordance with fashionable body shape. Design/methodology/approach Due to limited number of body measurements in historical sizing tables, it is impossible to redesign the morphology of old fashionable body with high accuracy by means of contemporary CAD. The developed method is based on two sources of information: first, historical sizing tables with body measurements; second, historical corsets. By combining both resources and applying virtual try-on technology, the full anthropometric database about the nineteenth century fashionable body shape has been organized and the parametric model of historical dress form has been generated. Findings The digital replica of deformable parametric dress form was created automatically in accordance with the historical sizing systems and the corsets construction. The process of reproduction of a historical dress form has been done with high accuracy due to substantial advantages of contemporary software. Originality/value This study shows new way of anthropometric data generating from the construction of close-fitting and compression undergarments. The developed method and the new database can be applied for each type of dress forms which were used in the second part of the nineteenth century to generate its digital replica in virtual reality. The new approach is joining the digital technologies and the professional knowledge as an important part of cultural heritage for studying, recreating and presenting historical costume.

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Becker, Mirco. « Felt-Concrete Composites in Architecture and Design ». Open Conference Proceedings 1 (15 février 2022) : 115. http://dx.doi.org/10.52825/ocp.v1i.84.

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The paper explores the possibilities of a composite of needle-felt fibres and cement-based matrix for designing and fabricating architectural elements. It summarizes the longer standing design-research undertaking in needle-felting as a novel method for creating materially graded objects without the use of formwork. The work is conducted on a design prototype of a chair to emphasise the integrative nature of this material system. This approach allows the study of all aspects from the fabrication process, the function of details, structural behaviour, and user experience. Needle fleeting has a long tradition in arts and craft for manually forming intricate objects such as figurines or applying ornaments to textile objects. The main feature of felt material is that it can bring fibrous material into a stable shape. This process has been digitized by Disney Research proposing needle felting as a way of 3D-printing fibrous material[1]. Becker et al. also proposed a robotic process for robotically 3D-printing felt shapes [2] which form the base for a material composite of felt-fibers and a cement based matrix. Their paper argues for functionally graded architectural elements where the composite of felt and cement can provide for tensile reinforcement, compressive strength, insulation, and different haptic surfaces. Based these methods here a replica of IKEA® Leifarne chair is realized, showcasing a range of felt-concrete composite applications integrated in a single object.

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Aljazaery, Ibtisam A., Haider Th Salim Alrikabi et Mustafa Rabea Aziz. « Combination of Hiding and Encryption for Data Security ». International Journal of Interactive Mobile Technologies (iJIM) 14, n^o 09 (17 juin 2020) : 34. http://dx.doi.org/10.3991/ijim.v14i09.14173.

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<pre>One of the techniques used in information security is the concealment technique, where the information to be hidden within another information medium to be saved in the process of messaging between two sides without detection. In this paper, an algorithm was proposed to conceal and encrypt data using several means.in order to ensure its preservation from detection and hackers. Wavelet transformer was used to change the shape of a wave of information (one and two-dimensional data) and its different mathematical formulas. Two sets of data were used, the first group used in a hidden process. The second group was considered as a means of both embedding and encryption. The data in the second group is reduced to the extent of sufficient for the modulation process, by extracting its high-value properties and then removing them from the mother's information wave. The process of encrypting of the two sets of data comes together using an exponential function. The result is undetectable information signals. Algorithms were built to hide and encrypt one and two-dimensional data. High-security signals and images were obtained. Decryption algorithms were built to return encrypted data to their original forms, and getting the replica data.</pre>

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Sandu, Ion, Claudiu Teodor Fleaca, Florian Dumitrache, Bogdan Alexandru Sava, Iuliana Urzica, Iulia Antohe, Simona Brajnicov et Marius Dumitru. « Shaping in the Third Direction ; Synthesis of Patterned Colloidal Crystals by Polyester Fabric-Guided Self-Assembly ». Polymers 13, n^o 23 (24 novembre 2021) : 4081. http://dx.doi.org/10.3390/polym13234081.

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A polyester fabric with rectangular openings was used as a sacrificial template for the guiding of a sub-micron sphere (polystyrene (PS) and silica) aqueous colloid self-assembly process during evaporation as a patterned colloidal crystal (PCC). This simple process is also a robust one, being less sensitive to external parameters (ambient pressure, temperature, humidity, vibrations). The most interesting feature of the concave-shape-pattern unit cell (350 μm × 400 μm × 3 μm) of this crystal is the presence of triangular prisms at its border, each prism having a one-dimensional sphere array at its top edge. The high-quality ordered single layer found inside of each unit cell presents the super-prism effect and left-handed behavior. Wider yet elongated deposits with ordered walls and disordered top surfaces were formed under the fabric knots. Rectangular patterning was obtained even for 20 μm PS spheres. Polyester fabrics with other opening geometries and sizes (~300–1000 μm) or with higher fiber elasticity also allowed the formation of similar PCCs, some having curved prismatic walls. A higher colloid concentration (10–20%) induces the formation of thicker walls with fiber-negative replica morphology. Additionally, thick-wall PCCs (~100 μm) with semi-cylindrical morphology were obtained using SiO2 sub-microspheres and a wavy fabric. The colloidal pattern was used as a lithographic mask for natural lithography and as a template for the synthesis of triangular-prism-shaped inverted opals.

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Somers, Kieran P., et David L. Cheung. « The Amyloidogenic Peptide Amyloid Beta(16–22) Displays Facet Dependent Conformation on Metal Surfaces ». Biophysica 2, n^o 2 (9 juin 2022) : 135–53. http://dx.doi.org/10.3390/biophysica2020015.

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Currently, it is not understood how metal nanoparticles influence the formation of protein fibrils, although recent literature highlights that the shape and chemical composition of such nanoparticles can strongly influence the process. Understanding this process at a fundamental level can potentially unlock routes to the development of new therapeutics, as well as novel materials for technological applications. This requires a microscopic picture of the behaviour of amyloidogenic proteins on metal surfaces. Using replica exchange molecular dynamics simulations, we investigate the conformation of the model amyloidogenic peptide, Aβ(16–22), on different gold and silver surfaces. The conformation of the peptide on gold surfaces also shows a strong facet dependence, with fibril-like conformations being promoted in the 100 surface and inhibited on the 111 surface. A smaller degree of facet dependence is seen for silver with the peptide behaving similar on both of these. The difference in the facet dependence can be related to the difference between direct adsorption onto the gold 111 surface, with a preference towards indirect (water mediated) adsorption onto the other surfaces. This new information on the behaviour of an amyloidogenic peptide on metal surfaces can give insight into the size-dependent effect of nanoparticles on fibril formation and the use of surfaces to control fibrillation.

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Choopani, Yahya, Mohsen Khajehzadeh et Mohammad Reza Razfar. « Optimal parameters of abrasive flow finishing for hip joint implants ». Proceedings of the Institution of Mechanical Engineers, Part B : Journal of Engineering Manufacture 235, n^o 11 (21 février 2021) : 1818–31. http://dx.doi.org/10.1177/0954405421995614.

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Total hip arthroplasty (THA) is one of the most well-known orthopedic surgeries in the world which involves the substitution of the natural hip joint by prostheses. In this process, the surface roughness of the femoral head plays a pivotal role in the performance of hip joint implants. In this regard, the nano-finishing of the femoral head of the hip joint implants to achieve a uniform surface roughness with the lowest standard deviation is a major challenge in the conventional and advanced finishing processes. In the present study, the inverse replica fixture technique was used for automatic finishing in the abrasive flow finishing (AFF) process. For this aim, an experimental setup of the AFF process was designed and fabricated. After the tests, experimental data were modeled and optimized to achieve the minimum surface roughness in the ASTM F138 (SS 316L) femoral head of the hip joint through the use of response surface methodology (RSM). The results confirmed uniform surface roughness up to the range of 0.0203 µm with a minimum standard deviation of 0.00224 for the femoral head. Moreover, the spherical shape deviation of the femoral head was achieved in the range of 7 µm. The RSM results showed a 99.71% improvement in the femoral head surface roughness (0.0007) µm under the optimized condition involving the extrusion pressure of 9.10 MPa, the number of finishing cycles of 95, and SiC abrasive mesh number of 1000.

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Lee, Heeran, Kyunghi Hong et Yejin Lee. « Development of 3D patterns for functional outdoor pants based on skin length deformation during movement ». International Journal of Clothing Science and Technology 29, n^o 2 (18 avril 2017) : 148–65. http://dx.doi.org/10.1108/ijcst-08-2016-0090.

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Purpose The seams of slim fit outdoor pants can be uncomfortable or even restrict body movement. To reduce discomfort, the authors need to determine optimal cutting lines in various designs that do not interfere with body movement. The purpose of this paper is to apply skin deformation mapping during movement to the ergonomic design of outdoor pants, focusing in particular on the 2D pattern generation of the crotch area in a 3D shape during movement. Design/methodology/approach A 3D shape and skin length deformation of the lower body were observed, including the crotch area, which is difficult to examine on the human body. To design ergonomic and streamlined outdoor pants, the authors selected seam lines where the changes in skin deformation are at their minimum based on the skin deformation mapping. In addition, the inseam along the medial thigh close to the crotch was removed to adjust the skin length of these areas, thereby increasing the extensible area of fabric necessary to adjust to a skin deformation. After selecting the seam lines, each of the 3D pattern blocks was generated by means of a 2D flattening method. In addition, the stress distribution of overlapped replica blocks along the crotch line during the 2D flattening process is a main independent factor to avoid deteriorating lower body movement as well as a good appearance. Findings Based on the results of skin deformation mapping of a human subject, this study suggested that it is best that the design line crosses where there is no skin deformation possible. And the pants were developed without the inner seam line at the upper medial thigh because of skin deformation of a large range of ±6 percent in the upper medial thigh during a 90° knee flexion or in the squatting down position. In a wear test, the developed 3D pattern without an inseam was rated higher than that with an inseam. This verified that removing the inseam, to prevent skin deformation of the medial upper thigh during knee flexion and squatting, is a logical decision. Regarding the correction of the overlapping area during arrangement of the replica, the appearance of the front of the pants was improved when 80 percent of the overlapping area was distributed near the point of the error source, which is the front of the male’s crotch line. Originality/value In this study, the crotch area, which has been difficult to observe in previous studies, were observed thoroughly and it was found that the length of the crotch curve did not increase during movement. In addition, skin deformation was mapped during a 90° knee flexion or in the squatting down position. It is expected that the overall process of developing 3D streamlined outdoor pants from 3D skin deformation mapping can be expanded to the development of patterns for other customized functional pants.

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Yoon, Mi Kyung, Yun Ja Nam et Woong Kim. « Classifying male upper lateral somatotypes using space vectors ». International Journal of Clothing Science and Technology 28, n^o 1 (7 mars 2016) : 115–29. http://dx.doi.org/10.1108/ijcst-03-2015-0043.

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Purpose – The purpose of this paper is to develop a method for defining and categorizing upper lateral somatotypes for clothing size systems used for clothing pattern creation based on directional angles of 3D space vectors. Design/methodology/approach – 3D data for 317 men in their twenties obtained from the fifth Size Korea survey were used in this study. Standard landmarks and surfaces were set on the 3D shapes, and six space vector angles of the lateral form were defined and measured. Relationships among the measurement results were clarified, and the results were compared with those obtained using existing classifying methods. Findings – The measurement of the defined directional angles indicated that the swayback type and bend-forward type had the two extreme values, and the straight type was between the two values. The analysis of the correlation between six directional angles indicated that some points in the lower area of the upper body had a high correlation with other points in the lower area. Researchlimitations/implications – The subjects of this study were limited to lateral somatotypes, and there is a need for future studies that focus on frontal somatotypes. This research is confined to the upper lateral somatotypes of men in their twenties. Further study is needed to extend the results of this study to other body types such as those of elderly and overweight persons. Practical implications – Major angle measurements quantified by the somatotypes can be specifically reflect in developing and revised to the right patterns which is spread body shell replica or individual pattern for MTM. Social implications – This objective somatotype analysis method can be involved in determining individual body somatotype of ordermade clothes or can provided the accurate information interactively to MTM automatic customized pattern making system. Originality/value – Accurate measurements of size, shape, and posture were applied and characterized to realize the process. Accuracy was improved compared to existing 2D analysis methods through three-dimensional analysis using directional space vector angles based on 3D forms.

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Thakur, Raviraj, et Gene Y. Fridman. « Low Cost, Ease-of-Access Fabrication of Microfluidic Devices Using Wet Paper Molds ». Micromachines 13, n^o 9 (27 août 2022) : 1408. http://dx.doi.org/10.3390/mi13091408.

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Rapid prototyping methods enable the widespread adoption of microfluidic technologies by empowering end-users from non-engineering disciplines to make devices using processes that are rapid, simple and inexpensive. In this work, we developed a liquid molding technique to create silicone/PDMS microfluidic devices by replica molding. To construct a liquid mold, we use inexpensive adhesive-backed paper, an acetate backing sheet, and an off-the-shelf digital cutter to create paper molds, which we then wet with predetermined amounts of water. Due to the immiscibility of water and PDMS, mold patterns can be effectively transferred onto PDMS similarly to solid molds. We demonstrate the feasibility of these wet paper molds for the fabrication of PDMS microfluidic devices and assess the influence of various process parameters on device yield and quality. This method possesses some distinct benefits compared to conventional techniques such as photolithography and 3D printing. First, we demonstrate that the shape of a channel’s cross-section may be altered from rectangular to semicircular by merely modifying the wetting parameters. Second, we illustrate how electrical impedance can be utilized as a marker for inspecting mold quality and identifying defects in a non-invasive manner without using visual tools such as microscopes or cameras. As a proof-of-concept device, we created a microfluidic T-junction droplet generator to produce water droplets in mineral oil ranging in size from 1.2 µL to 75 µL. We feel that this technology is an excellent addition to the microfluidic rapid prototyping toolbox and will find several applications in biological research.

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Liciu, Eduard, Maria Miruna Mihai, Ștefana Carp, Laura Popa, Camelia Vreme et Vlad Costel. « 3D PRINTING IN PEDIATRIC ORTHOPEDICS – THE NEW GENERATION OF PREOPERATIVE PLANNING IN THE FIELD OF PEDIATRIC ORTHOPEDICS ». Journal of Surgical Sciences 7, n^o 3 (26 décembre 2020) : 85–92. http://dx.doi.org/10.33695/jss.v7i3.390.

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The evolution of modern medicine, in its continuous developing process, is highly connected with the progress achieved in the medical branch of technology. Regarding the surgical specialties, the technological progress breakthroughs may determine the appearance of new diagnosis techniques, but also shape innovative treatments, leading to superior therapeutic results. In the surgical treatment as a whole, an essential role is played by the Medical Imagistics. They either offer the much-needed visual support in order to reach an accurate diagnosis, or guide the surgeon in choosing a certain type of intervention. The importance of Imagistics is indisputable. It has also been proven so in intraoperatory guidance and monitoring the patient in post-surgery. In the evolution of medical Imagistics, after the transition to digital imaging, followed by graphic 3D reconstructions based on CT and MRI data, we find ourselves contemporary with a new turning point announcing a technological revolution: the transition from virtual 3D models to tangible 3D replica. Since the beginning, the 3D printing technology has been of great importance to the field of medical research and, once the technique gained popularity, it became a modern tool for many medical specialties, in particular for cranio-maxillofacial surgery, orthopedics, oncology, neurosurgery. The 3D printing technology managed to transgress dated barriers by facilitating the manufacturing of implants or implement new treatments in regenerative medicine. The purpose of this original paper is to present our 3D printing work protocol and general conclusions after 5 years of implementing 3D printing in pediatric orthopedics.

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Golibrzuch, Matthias, Thomas L. Maier, Moritz J. Feil, Katharina Krischer et Markus Becherer. « Tuning the feature size of nanoimprinting stamps : A method to enhance the flexibility of nanoimprint lithography ». Journal of Applied Physics 131, n^o 12 (28 mars 2022) : 124301. http://dx.doi.org/10.1063/5.0079282.

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In the field of nanoimprinting lithography, fabricating large-area imprinting stamps is often the most time- and resource-consuming step. Specifically in research, it is often not reasonable to produce a new imprinting stamp for each new experimental configuration. Therefore, the lack of flexibility in feature sizes makes prototyping and tailoring the feature sizes according to their application challenging. To overcome these restrictions, we developed an imprinting stamp reproduction and tuning method which enables the size of the features of existing imprinting stamps to be tuned within nanometer precision. For replication, we first fabricate a chromium nanoisland array on silicon dioxide using the to-be tuned imprinting stamp. Then, the silicon dioxide is anisotropically etched in a reactive ion etching process with chromium as a hard mask. The formed replica of the imprinting stamp is subsequently tuned in an isotropic etching step with hydrofluoric acid. The method enables us to tune the size of the features of our nanoimprinting stamps within nanometer precision without influencing their shape with a yield above 96%. The tuned stamps are then used to fabricate metal nanoisland arrays with the respective tuned sizes. To evaluate the influence of the feature sizes, we exemplarily study the plasmonic resonance of gold nanoisland arrays fabricated using stamps with different feature diameters. Here, we see a good agreement between measured and simulated plasmonic resonance wavelengths of the samples. Hence, with the tuning method, we can tailor specific size-dependent properties of our nanoisland arrays according to individual experiments and applications.

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Ranito, Cláudia M. S., Fernando A. Costa Oliveira et João P. Borges. « Hydroxyapatite Foams for Bone Replacement ». Key Engineering Materials 284-286 (avril 2005) : 341–44. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.341.

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Hydroxyapatite, often in the form of synthetic porous blocks, has been used in the repair of bone defects for over 20 years owing to its biocompatibility and osseoconductive behaviour. Bone ingrowth requires the existence of open and interconnected pores with diameters larger than 150 µm for proper circulation of nutrients. Hence, currently available materials are characterised by poor mechanical properties. Collapse of such products is therefore a major source of concern to surgeons using these weak materials in bone surgery. There is a need to develop stronger highly porous structures through adequate control over the size, shape and volume fraction of pores. In this work, highly porous open-cell hydroxyapatite foams were fabricated by the polymer foam replication process, where two types of polyurethane (PU) foams were infiltrated with optimised slurries containing appropriate binders and ceramic particles, followed by the removal of excess slurry, burning out of the polymer to leave a ceramic replica of the polyurethane and finally high temperature sintering. Open-cell HAP foams with porosities of about 80% were obtained, i.e. 30% higher than that determined for commercial ones (50%). Many of the commercial foam cells approach 500 µm in diameter whereas the developed foam cell size ranged from 300 up to 500 µm. The ultimate compressive strength of the developed foams (1-2 MPa) was found to be higher than that recorded for the commercial ones (0.7 MPa) indicating that these foams can more easily be modelled in theatre. Both the elastic moduli and the compressive strength of the developed foams were found to increase with increasing of the relative density, in accordance with the predictions of available micro-mechanical models.

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Chung, Joo-Hong, Hyung-Suk Jung et Hyun-Ki Choi. « Flexural Strength and Stiffness of Donut-Type Voided Slab ». Applied Sciences 12, n^o 12 (7 juin 2022) : 5782. http://dx.doi.org/10.3390/app12125782.

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The voided slab system has been known as an effective technique to replace a heavy reinforced concrete slab system without the decrease in flexural strength. However, according to the previous studies, the flexural capacities such as flexural strength, stiffness and ductility of the voided slabs were practically lower than that of the solid slabs depending on the void shapes and details. Therefore, in this study, an analytical and experimental study were conducted to derive the optimal void shape and details focused on the flexural capacities of voided slabs. Based on a finite element (FE) analysis, a donut-type void shaper, which was a hexahedron with rounded edges and a hole penetrating the center, was suggested as the optimal shape in voided slabs, and an experimental study was conducted to verify flexural capacities of the donut-type voided slab. The flexural strength, stiffness and deflection of the donut-type voided slab were investigated by void shape and fixing method of void shaper as variables. The ductility of voided slab was also evaluated, because ductility is as important as strength for the safe design of slab member. The test results showed that the flexural strength of the donut-type voided slabs was equivalent to 98% and 105% that of the solid RC specimen, and the donut-type voided slab specimens had enough ductility for the flexural member. The stiffness of the donut-type voided slab was decreased about 8~9% compared with the solid slab, but it was improved up to 7% compared to the non-donut-type voided slab. Based on test results, the flexural design method of the donut-type voided slab associated with the void shape and fixing device of void shaper was suggested, and it was confirmed that the donut-type voided slab is one of the efficient alternatives to replace heavy flat plate slabs.

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Messer, Dolores, Michelle S. Svendsen, Anders Galatius, Morten T. Olsen, Vedrana A. Dahl, Knut Conradsen et Anders B. Dahl. « Measurement error using a SeeMaLab structured light 3D scanner against a Microscribe 3D digitizer ». PeerJ 9 (20 août 2021) : e11804. http://dx.doi.org/10.7717/peerj.11804.

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Background Geometric morphometrics is a powerful approach to capture and quantify morphological shape variation. Both 3D digitizer arms and structured light surface scanners are portable, easy to use, and relatively cheap, which makes these two capturing devices obvious choices for geometric morphometrics. While digitizer arms have been the “gold standard”, benefits of having full 3D models are manifold. We assessed the measurement error and investigate bias associated with the use of an open-source, high-resolution structured light scanner called SeeMaLab against the popular Microscribe 3D digitizer arm. Methodology The analyses were based on 22 grey seal (Halichoerus grypus) skulls. 31 fixed anatomical landmarks were annotated both directly using a Microscribe 3D digitizer and on reconstructed 3D digital models created from structured light surface scans. Each skull was scanned twice. Two operators annotated the landmarks, each twice on all the skulls and 3D models, allowing for the investigation of multiple sources of measurement error. We performed multiple Procrustes ANOVAs to compare the two devices in terms of within- and between-operator error, to quantify the measurement error induced by device, to compare between-device error with other sources of variation, and to assess the level of scanning-related error. We investigated the presence of general shape bias due to device and operator. Results Similar precision was obtained with both devices. If landmarks that were identified as less clearly defined and thus harder to place were omitted, the scanner pipeline would achieve higher precision than the digitizer. Between-operator error was biased and seemed to be smaller when using the scanner pipeline. There were systematic differences between devices, which was mainly driven by landmarks less clearly defined. The factors device, operator and landmark replica were all statistically significant and of similar size, but were minor sources of total shape variation, compared to the biological variation among grey seal skulls. The scanning-related error was small compared to all other error sources. Conclusions As the scanner showed precision similar to the digitizer, a scanner should be used if the advantages of obtaining detailed 3D models of a specimen are desired. To obtain high precision, a pre-study should be conducted to identify difficult landmarks. Due to the observed bias, data from different devices and/or operators should not be combined when the expected biological variation is small, without testing the landmarks for repeatability across platforms and operators. For any study necessitating the combination of landmark measurements from different operators, the scanner pipeline will be better suited. The small scanning-related error indicates that by following the same scanning protocol, different operators can be involved in the scanning process without introducing significant error.

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Suri, Srinivas, M. Manzoor Hussain et Abhijit Dutta. « Superplastic Forming Using Rectangular Shape Dies for Process Optimization ». International Journal of Engineering & ; Technology 7, n^o 3.6 (4 juillet 2018) : 302. http://dx.doi.org/10.14419/ijet.v7i3.6.15085.

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Superplastic forming is a useful tool for the fabrication of complex parts used in the aircraft and automobile industries. Superplastic forming (SPF) of sheet metal has been used to produce very complex shapes and integrated structures that are often lighter and stronger than the assemblies they replace. In the present work design and fabrication of a Superplastic forming die was taken up for producing a rectangular shape and studied the process parameters. The sheets are made of Sn-Pb alloy in the ratio of 60-40. The Superplastic forming operation occurs where the flow stress of the sheet material is low. The sheet is placed in a rectangular die, which can have a simple to complex geometry, representative of the final part to be produced. The sheet is formed into the rectangular shape using gas pressure. Various pressures were applied and parameter like sheet thickness, depth with respect to time and thickness variations of a rectangular shape.

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Suri, Srinivas, M. Manzoor Hussain et Abhijit Dutta. « Superplastic Forming Using Rectangular Shape Dies for Process Optimization ». International Journal of Engineering & ; Technology 7, n^o 3.6 (4 juillet 2018) : 302. http://dx.doi.org/10.14419/ijet.v7i3.6.15120.

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Superplastic forming is a useful tool for the fabrication of complex parts used in the aircraft and automobile industries. Superplastic forming (SPF) of sheet metal has been used to produce very complex shapes and integrated structures that are often lighter and stronger than the assemblies they replace. In the present work design and fabrication of a Superplastic forming die was taken up for producing a rectangular shape and studied the process parameters. The sheets are made of Sn-Pb alloy in the ratio of 60-40. The Superplastic forming operation occurs where the flow stress of the sheet material is low. The sheet is placed in a rectangular die, which can have a simple to complex geometry, representative of the final part to be produced. The sheet is formed into the rectangular shape using gas pressure. Various pressures were applied and parameter like sheet thickness, depth with respect to time and thickness variations of a rectangular shape.

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Mazzocato, Sara, Giacomo Marchioro et Claudia Daffara. « Feasibility and performance analysis in 3D printing of artworks using laser scanning microprofilometry ». ACTA IMEKO 11, n^o 1 (31 mars 2022) : 7. http://dx.doi.org/10.21014/acta_imeko.v11i1.1098.

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We investigated optical scanning microprofilometry and conoscopic holography sensors as nondestructive testing and evaluation tools in archeology for obtaining an accurate 3D printed reproduction of the data. The modular microprofilometer prototype allows a versatile acquisition of different materials and shapes producing a high-quality dataset that enables surface modelling at micrometric scales from which a "scientific" replica can be obtained through 3D printing technologies. As exemplar case study, an archeological amphora was acquired and 3D printed. In order to test the feasibility and the performance of the whole process chain from the acquisition to the reproduction, we propose a statistical multiscale analysis of the surface signal of object and replica based on metrological parameters. This approach allows to demonstrate that the accuracy of the 3D printing process preserves the range of spatial wavelengths that characterizes the surface features of interest within the technology capabilities. This work extends the usefulness of the replicas from museum exposition to scientific applications.

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Ernst, Eric M., Ben C. Church, Christopher S. Gaddis, Robert L. Snyder et Kenneth H. Sandhage. « Enhanced hydrothermal conversion of surfactant-modified diatom microshells into barium titanate replicas ». Journal of Materials Research 22, n^o 5 (mai 2007) : 1121–27. http://dx.doi.org/10.1557/jmr.2007.0169.

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The three-dimensional nanostructured SiO2-based microshells of diatoms have been converted into nanocrystalline BaTiO3 via a series of shape-preserving reactions. The microshells, obtained as diatomaceous earth, were first exposed to a surfactant-induced dissolution/reprecipitation process [C.E. Fowler, et al., Chem. Phys. Lett.398, 414 (2004)] to enhance the microshell surface area, without altering the microshell shape. The SiO2 microshells were then converted into anatase TiO2 replicas via reaction with TiF4 gas and then humid oxygen. Hydrothermal reaction with a barium hydroxide-bearing solution then yielded three-dimensional nanocrystalline microshell replicas composed of BaTiO3. The enhanced surface area of the surfactant-treated microshells resulted in faster conversion into phase-pure BaTiO3 at 100 °C.

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Lee, Seung-Hun, Chan-Joo Lee, Kyung-Hun Lee, Jung-Min Lee, Byung-Min Kim et Dae-Cheol Ko. « Influence of Tool Shape on Hole Clinching for Carbon Fiber-Reinforced Plastic and SPRC440 ». Advances in Mechanical Engineering 6 (1 janvier 2014) : 810864. http://dx.doi.org/10.1155/2014/810864.

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Carbon fiber-reinforced plastic (CFRP) is a lightweight material that can potentially replace structural steel components in automobiles. The hole-clinching process is a mechanical clinching technique for joining brittle or low-ductility materials, such as CFRP, with ductile materials. In this study, the influence of tool shape on the hole-clinching process for CFRP and SPRC440 was investigated using FE-analysis and experiments. The parameters of the tool shape investigated were the punch corner radius and the punch diameter. The geometrical interlocking shapes of hole-clinched joints were characterized by neck thickness and undercut. Based on the desired joint strength of 2.5 kN, hole-clinching tools were designed on the basis of the relationship between joint strength and geometrical interlocking. FE-analysis and hole-clinching experiments were performed with the designed hole-clinching tools to investigate the geometrical interlocking shape as well as joinability, including neck fracture, undercut, and hole expansion, resulting from changes in tool parameters. Joint strength was evaluated to verify the effectiveness of hole clinching by a single lap shear test.

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Chen, Yan, Song Wei Wang, Hong Wu Song et Shi Hong Zhang. « Forging Process Design and Simulation Optimization of a Complex-Shaped Aluminium Alloy Component ». Materials Science Forum 941 (décembre 2018) : 784–89. http://dx.doi.org/10.4028/www.scientific.net/msf.941.784.

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In order to meet the requirements of lightweight and replace steel with the aluminum for a component on the high speed rail, the forging process of a complex-shaped aluminum alloy component was researched and the parameters were optimized with the DEFORM-3D finite element simulation technology. The qualified products were finally obtained instead of the original steel castings by reducing weight of 65%. It is noted that the parts with complicated shape and non-symmetry, metal flow uneven during forging process that lead to incomplete forming, higher forging pressure problems. In this paper, such problems were analyzed couple with numerical simulation method based on a certain forming pressure. Moreover, the model and slot was reasonably designed. In addition, the size of blank was constantly optimized to change the metal flows direction and cavity filling mode. Finally, the forgings with good surface quality and mechanical properties were obtained by production test, and can be used as reference for this kind of forging components.

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Dao, Van Luu, Sheng Dun Zhao, Wen Jie Lin et Xiao Mei Yuan. « Impact of Process Parameters on the Auto Claw-Pole Thixoforming Process ». Advanced Materials Research 295-297 (juillet 2011) : 1625–30. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.1625.

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Thixoforming of steel is a potential forming technology, which can realize near-net-shape forming process with good quality in one forming step. In this paper, thixoforming process was used to replace the conventional hot forging process to form the auto claw-pole. The finite element code Forge2008Ó was used to simulate the auto claw-pole thixoforming process. The impact of three main process parameters such as initial billet temperature, punch speed and die temperature on the forming process were investigated. The reasonable process parameters for the auto claw-pole thixoforming were obtained: initial billet temperature 1430~1440°C, punch speed 100~200mm/s and die temperature 300~400°C.

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Nemeša, Ineta. « Blindstitch machines for men suit manufacturing : Part 2 ». Tekstilna industrija 69, n^o 3 (2021) : 41–46. http://dx.doi.org/10.5937/tekstind2103041n.

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Different blindstitch machines are used in men suit industrial manufacturing process to replace traditional manual sewing techniques and ensure high work process productivity. The waistband of the trousers is felled with special machines of stitches 103. Beltloop machines process double-folded belt loops for trousers with or without inserted tape. To create 3D shape to lapels and collars of jacket padding machines are used. Spot tacking machines fix together two or more layers of fabric with stitches invisible on the face side of the garment. Machines for felling undercollars create V-shaped zig-zag stitches 314. Two kind of machines are used to fell the lining in the armhole and bottom of the sleeve. Blindstitch machines for certain technological operations are manufactured by companies: Strobel, Maier, Japsew, Global, others.

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Haratym, R., M. Sieczka, R. Biernacki et J. Kwapisz. « Shape Errors, Internal Porosity, Linear Dimensions Accuracy and Allowances for the Machining of Castings Made in the Replicast CS Process ». Archives of Foundry Engineering 14, n^o 3 (8 août 2014) : 25–28. http://dx.doi.org/10.2478/afe-2014-0055.

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Abstract This research presents comprehensive assessment of the precision castings quality made in the Replicast CS process. The evaluation was made based on quality of the surface layer, shape errors and the accuracy of the linear dimensions. Studies were carried out on the modern equipment, among other things a Zeiss Calypso measuring machine and profilometer were used. Obtained results allowed comparing lost wax process models and Replicast CS process.

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WÓJS, ARKADIUSZ, LESZEK BRYJA, ANNA GŁADYSIEWICZ, JAN MISIEWICZ et MAREK POTEMSKI. « PHOTOLUMINESCENCE OF IMPURITY-BOUND EXCITONS AND TRIONS IN MAGNETIC FIELDS ». International Journal of Modern Physics B 21, n^o 08n09 (10 avril 2007) : 1558–62. http://dx.doi.org/10.1142/s0217979207043191.

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Recombination spectrum of excitons and positive trions is studied by two-beam magneto-photoluminescence of a two-dimensional hole gas. For acceptor-bound trions a low-energy cyclotron replica is observed, corresponding to a hole shake-up process. The experiment is supplemented by realistic numerical calculations, allowing for identification of individual transitions and connecting the splitting of the shake-up line directly with the hole mass.

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Bolleyer, Nicole, Anika Gauja et Patricia Correa. « Legal Regulation and the Juridification of Party Governance ». Comparative Politics 53, n^o 1 (1 octobre 2020) : 117–50. http://dx.doi.org/10.5129/001041520x15858647604599.

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Although democratic states increasingly regulate political parties, we know little about how legal environments shape parties' internal lives. This article conceptualizes and measures the "juridification" of party organizations' conflict regulation regimes: that is, the extent to which parties replicate external legal standards (e.g. norms of due process) within their own procedures. Formulating hypotheses on juridification within different parties and legal environments, we examine intra-party juridification across four democracies with most different party law provisions. While party juridification varies—reflecting parties' ideological differences—in contexts where organizational governance remains unregulated, once intra-organizational governance is subject to statutory constraints, parties emulate legal norms embedded in the state legal system, transcending what is legally required, which has important repercussions for how the law shapes civil society organizations generally.

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Ji, Myung, Mohammed Bazroun, In Cho, W. Slafer, Rana Biswas et Jaeyoun Kim. « Mechano-Triboelectric Analysis of Surface Charge Generation on Replica-Molded Elastomeric Nanodomes ». Micromachines 12, n^o 12 (27 novembre 2021) : 1460. http://dx.doi.org/10.3390/mi12121460.

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Replica molding-based triboelectrification has emerged as a new and facile technique to generate nanopatterned tribocharge on elastomer surfaces. The “mechano-triboelectric charging model” has been developed to explain the mechanism of the charge formation and patterning process. However, this model has not been validated to cover the full variety of nanotexture shapes. Moreover, the experimental estimation of the tribocharge’s surface density is still challenging due to the thick and insulating nature of the elastomeric substrate. In this work, we perform experiments in combination with numerical analysis to complete the mechano-triboelectrification charging model. By utilizing Kelvin probe force microscopy (KPFM) and finite element analysis, we reveal that the mechano-triboelectric charging model works for replica molding of both recessed and protruding nanotextures. In addition, by combining KPFM with numerical electrostatic modeling, we improve the accuracy of the surface charge density estimation and cross-calibrate the result against that of electrostatic force microscopy. Overall, the regions which underwent strong interfacial friction during the replica molding exhibited high surface potential and charge density, while those suffering from weak interfacial friction exhibited low values on both. These multi-physical approaches provide useful and important tools for comprehensive analysis of triboelectrification and generation of nanopatterned tribocharge. The results will widen our fundamental understanding of nanoscale triboelectricity and advance the nanopatterned charge generation process for future applications.

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Dao, Van Luu, Sheng Dun Zhao et Wen Jie Lin. « Numerical Simulation of the Auto Claw-Pole Thixoforming Process ». Applied Mechanics and Materials 66-68 (juillet 2011) : 1605–10. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1605.

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Thixoforming is an effective near-net-shape forming process to produce components with complex geometry and in fewer forming steps. In this study, thixoforming was used to replace the conventional hot forging to form the auto claw-pole. The finite element code Forge2008Ó was used to simulate the auto claw-pole thixoforming process. The results show that initial billet temperature, punch speed, die temperature and friction have strong impact on the forming process. Finally, the reasonable process parameters for the auto claw-pole thixoforming were obtained: initial billet temperature 1430~1440°C, punch speed 100~200mm/s and die temperature 300~400°C.

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Scheithauer, Uwe, Florian Kerber, Alexander Füssel, Stefan Holtzhausen, Wieland Beckert, Eric Schwarzer, Steven Weingarten et Alexander Michaelis. « Alternative Process Routes to Manufacture Porous Ceramics—Opportunities and Challenges ». Materials 12, n^o 4 (22 février 2019) : 663. http://dx.doi.org/10.3390/ma12040663.

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Porous ceramics can be realized by different methods and are used for various applications such as cross-flow membranes or wall-flow filters, porous burners, solar receivers, structural design elements, or catalytic supports. Within this paper, three different alternative process routes are presented, which can be used to manufacture porous ceramic components with different properties or even graded porosity. The first process route is based on additive manufacturing (AM) of macro porous ceramic components. The second route is based on AM of a polymeric template, which is used to realize porous ceramic components via replica technique. The third process route is based on an AM technology, which allows the manufacturing of multimaterial or multiproperty ceramic components, like components with dense and porous volumes in one complex-shaped component.

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Zhang, J., M. Sahli, J. C. Gelin et C. Khan-Malek. « Experimental analysis of the evolution of the physical properties of pyramidal-shaped metallic replicas made using the MIM process ». International Journal of Advanced Manufacturing Technology 68, n^o 5-8 (24 mars 2013) : 1063–74. http://dx.doi.org/10.1007/s00170-013-4897-x.

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Liu, Xing, Huai-Xin Chen et Bi-Yuan Liu. « Dynamic Anchor : A Feature-Guided Anchor Strategy for Object Detection ». Applied Sciences 12, n^o 10 (12 mai 2022) : 4897. http://dx.doi.org/10.3390/app12104897.

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The majority of modern object detectors rely on a set of pre-defined anchor boxes, which enhances detection performance dramatically. Nevertheless, the pre-defined anchor strategy suffers some drawbacks, especially the complex hyper-parameters of anchors, seriously affecting detection performance. In this paper, we propose a feature-guided anchor generation method named dynamic anchor. Dynamic anchor mainly includes two structures: the anchor generator and the feature enhancement module. The anchor generator leverages semantic features to predict optimized anchor shapes at the locations where the objects are likely to exist in the feature maps; by converting the predicted shape maps into location offsets, the feature enhancement module uses the high-quality anchors to improve detection performance. Compared with the hand-designed anchor scheme, dynamic anchor discards all pre-defined boxes and avoids complex hyper-parameters. In addition, only one anchor box is predicted for each location, which dramatically reduces calculation. With ResNet-50 and ResNet-101 as the backbone of the one-stage detector RetinaNet, dynamic anchor achieved 2.1 AP and 1.0 AP gains, respectively. The proposed dynamic anchor strategy can be easily integrated into the anchor-based detectors to replace the traditional pre-defined anchor scheme.

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Schillinger, Kerstin, Alex Mesoudi et Stephen J. Lycett. « Copying Error and the Cultural Evolution of “Additive” vs. “Reductive” Material Traditions : An Experimental Assessment ». American Antiquity 79, n^o 1 (janvier 2014) : 128–43. http://dx.doi.org/10.7183/0002-7316.79.1.128.

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AbstractCopying errors that occur during the manufacture of artifactual traditions are potentially a major source of variation. It has been proposed that material items produced via “additive” processes (e.g., pottery) will possess less variation than traditions produced via “reductive” processes (e.g., stone knapping). The logic of this premise is that “additive” production methods more readily allow for the reversal of copying errors compared to strictly “reductive-only” processes. Here, we tested this hypothesis in shape data using an experimental framework in which we generated and statistically analyzed morphometry (size-adjusted) shape data under controlled and replicable conditions. Participants engaged in one of two alternative conditions: an irreversible (“reductive-only”) manufacturing process or a reversible (“additive-reductive”) process. With a number of factors held constant, participants were required to copy the shape of a “target form” as accurately as possible using a standardized block of plasticine and a steel table knife. Results demonstrated statistically greater levels of shape-copying errors in the replicas produced in the reductive-only condition. This indicates that “mutation rates” in the shape attributes of artifactual traditions produced via reductive processes are inherently greater than those produced via alternative means. Several implications for the study of variation in artifactual traditions are discussed.

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Photiou, Demetris, Stelios Avraam, Francesco Sillani, Fabrizio Verga, Olivier Jay et Loucas Papadakis. « Experimental and Numerical Analysis of 3D Printed Polymer Tetra-Petal Auxetic Structures under Compression ». Applied Sciences 11, n^o 21 (4 novembre 2021) : 10362. http://dx.doi.org/10.3390/app112110362.

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Auxetic structures possess a negative Poisson ratio (ν < 0) as a result of their geometrical configuration, which exhibits enhanced indentation resistance, fracture toughness, and impact resistance, as well as exceptional mechanical response advantages for applications in defense, biomedical, automotive, aerospace, sports, consumer goods, and personal protective equipment sectors. With the advent of additive manufacturing, it has become possible to produce complex shapes with auxetic properties, which could not have been possible with traditional manufacturing. Three-dimensional printing enables easy and precise control of the geometry and material composition of the creation of desirable shapes, providing the opportunity to explore different geometric aspects of auxetic structures with a variety of different materials. This study investigated the geometrical and material combinations that can be jointly tailored to optimize the auxetic effects of 2D and 3D complex structures by integrating design, modelling approaches, 3D printing, and mechanical testing. The simulation-driven design methodology allowed for the identification and creation of optimum auxetic prototype samples manufactured by 3D printing with different polymer materials. Compression tests were performed to characterize the auxetic behavior of the different system configurations. The experimental investigation demonstrated a Poisson’s ration reaching a value of ν = −0.6 for certain shape and material combinations, thus providing support for preliminary finite element studies on unit cells. Finally, based on the experimental tests, 3D finite element models with elastic material formulations were generated to replicate the mechanical performance of the auxetic structures by means of simulations. The findings showed a coherent deformation behavior with experimental measurements and image analysis.

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Gritsyuk, Vasily, Evgeny Smolentsev, Dmitriy Krokhin et Aleksandr Pechagin. « Improving the Accuracy and Quality of the Surface Layer of Products by Local Magnetic Pulse Processing ». MATEC Web of Conferences 346 (2021) : 01029. http://dx.doi.org/10.1051/matecconf/202134601029.

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This article discusses development of technological modes and the process of stabilizing the properties of surface layers of large-sized parts, ensuring accuracy and stability of the products’ shape during their manufacture and operation, while using combined processing methods that replace costly heat treatment at mechanical engineering enterprises.

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Tauhiduzzaman, Mohammad, Islam Hafez, Douglas Bousfield et Mehdi Tajvidi. « Modeling Microwave Heating and Drying of Lignocellulosic Foams through Coupled Electromagnetic and Heat Transfer Analysis ». Processes 9, n^o 11 (9 novembre 2021) : 2001. http://dx.doi.org/10.3390/pr9112001.

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Microwave drying of suspensions of lignocellulosic fibers has the potential to produce porous foam materials that can replace materials such as expanded polystyrene, but the design and control of this drying method are not well understood. The main objective of this study was to develop a microwave drying model capable of predicting moisture loss regardless of the shape and microwave power input. A microwave heating model was developed by coupling electromagnetic and heat transfer physics using a commercial finite element code. The modeling results predicted heating time behavior consistent with experimental results as influenced by electromagnetic fields, waveguide size and microwave power absorption. The microwave heating modeling accurately predicted average temperature increase for 100 cm3 water domain at 360 and 840 W microwave power inputs. By dividing the energy absorption by the heat of vaporization, the amount of water evaporation in a specific time increment was predicted leading to a novel method to predict drying. Using this method, the best time increments, and other parameters were determined to predict drying. This novel method predicts the time to dry cellulose foams for a range of sample shapes, parameters, material parameters. The model was in agreement with the experimental results.

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Moravčíková, Jana, et Peter Pokorný. « Design of Complex Component for Determination of a CNC Milling Machines Accuracy ». Key Engineering Materials 703 (août 2016) : 22–26. http://dx.doi.org/10.4028/www.scientific.net/kem.703.22.

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The article is focused on the design of complex component to determine competence CNC milling machines designed to produce shapes with geometric tolerances by observing the shape, orientation and position of the standard EN ISO 1101. 3D model of a technological process for the production of complex components, it will contain the complete design of tools and cutting parameters for individual milling strategy, select clamping and workpiece material, a preview of the generated routing strategies and paths cut surface after each of their simulated. For milling machines with the so-called measurement system for machine OMM (On Machine Measurement), the proposal for a comprehensive parts serve as a reference in determining the accuracy of their measurements of geometric and dimensional tolerances. The main activity of systems OMM is the replace of the tool clamped in the spindle of milling machines with special touch probe which senses by the touch surface contours of produced parts.

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Gschwenter, Viviane L. S., Rejane M. C. Tubino, Weslei M. Ambrós, Gerson L. Miltzarek, Carlos Hoffmann Sampaio, Josep Oliva Moncunill, Bogdan Grigore Cazacliu et Denise C. C. Dal Molin. « Production of High-Quality Coarse Recycled Aggregates through a Two-Stage Jigging Process ». Minerals 12, n^o 5 (25 avril 2022) : 532. http://dx.doi.org/10.3390/min12050532.

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The use of recycled aggregates (RA) to replace natural aggregates (NA) in new concrete production has been pointed out as one of the main strategies to close the loop of construction materials. However, producing RA with properties similar to those of NA has been challenging, since current recycling methods struggle to remove contaminants like ceramics and mortar, whose presence impairs RA properties. In this study, a processing route consisting of a two-stage separation in hydraulic jig was tested, aiming to produce RA from a representative sample of Brazilian construction and demolition waste. All material streams generated in the tests were characterized in terms of composition, size distribution, density, shape index, and water absorption. The results indicated the possibility to produce a high-quality RA, containing more than 99.5% mass of concrete, with adequate properties to replace NA in new concrete production. Also, a conventional RA with suitable properties for downcycling uses (for example, base and sub-base material) could be obtained as a co-product. Finally, the results showed it was possible to recover more than 75% of the original concrete in Construction and Demolition Waste CDW, avoiding its disposal as waste.

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Gschwenter, Viviane L. S., Rejane M. C. Tubino, Weslei M. Ambrós, Gerson L. Miltzarek, Carlos Hoffmann Sampaio, Josep Oliva Moncunill, Bogdan Grigore Cazacliu et Denise C. C. Dal Molin. « Production of High-Quality Coarse Recycled Aggregates through a Two-Stage Jigging Process ». Minerals 12, n^o 5 (25 avril 2022) : 532. http://dx.doi.org/10.3390/min12050532.

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The use of recycled aggregates (RA) to replace natural aggregates (NA) in new concrete production has been pointed out as one of the main strategies to close the loop of construction materials. However, producing RA with properties similar to those of NA has been challenging, since current recycling methods struggle to remove contaminants like ceramics and mortar, whose presence impairs RA properties. In this study, a processing route consisting of a two-stage separation in hydraulic jig was tested, aiming to produce RA from a representative sample of Brazilian construction and demolition waste. All material streams generated in the tests were characterized in terms of composition, size distribution, density, shape index, and water absorption. The results indicated the possibility to produce a high-quality RA, containing more than 99.5% mass of concrete, with adequate properties to replace NA in new concrete production. Also, a conventional RA with suitable properties for downcycling uses (for example, base and sub-base material) could be obtained as a co-product. Finally, the results showed it was possible to recover more than 75% of the original concrete in Construction and Demolition Waste CDW, avoiding its disposal as waste.

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Halouani, Ali, Yu Ming Li, Boussad Abbès et Y. Q. Guo. « Simulation of Axi-Symmetrical Forging Process by “Inverse Approach” ». Materials Science Forum 675-677 (février 2011) : 1007–10. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.1007.

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The simplified method called Inverse Approach (I.A.) has been developed by Batoz, Guo et al.[1] for the sheet forming modelling. They are less accurate but much faster than classical incremental approaches. The main aim of the present work is to study the feasibility of the I.A. for the axi-symmetric forging process modelling. In contrast to the classical incremental methods, the I.A. exploits the known shape of the final part and executes the calculation from the final part to the initial billet. Two assumptions are used in this study: the assumption of proportional loading for cold forging gives an integrated constitutive law without considering the strain path and the viscoplasticity, the assumption of contact between the part and tools allows to replace the tool actions by nodal forces without contact treatment. The comparison with Abaqus shows that the I.A. can obtain a good strain distribution and it will be a good tool for the preliminary preform design.

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Hurmuz, Mihai, Mihai Ionac, Carmen Tatu, Daniela Puscasiu, Catalin Adrian Miu, Sergiu Galatanu et Fabian Tatu. « A 3D Bioprinted Human Meniscus Shape Enriched with Mesenchymal Cells ». Applied Sciences 11, n^o 24 (10 décembre 2021) : 11733. http://dx.doi.org/10.3390/app112411733.

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Background and objectives: Regenerative medicine, with its massive development over the years, has the potential to solve some of the most problematic medical issues, such as functional organ transplantation. The aim of this study was to create a human meniscal shape 3D-printed enriched with human adipose-derived mesenchymal cells. Materials and Methods: Human infrapatellar fat pad was harvested, and mesenchymal cells were isolated. The mesenchymal stem cells were differentiated to the chondrocite lineage and a hydrogel (a nanofibrillar cellulose, sodium alginate, D-mannitol, and Hepes buffer solution combination) cell mixture was bioprinted to create three human-size meniscus structures. The obtained structures were evaluated regarding the cell viability, appropriate size in relation to a native meniscus, and some mechanical characteristics. Results: The human meniscal shape created respected the anatomic characteristic of a native structure. Cell viability of approximately 97% and extracellular matrix formation after the printing process were observed. The mean maximum force for the meniscus with mesenchymal cells was 6.5 N (+/−0.5 N) compared to the mean maximum force for the native meniscus of 10.32 N (+/−0.7 N), which is statistically relevant (p < 0.01). Conclusion: This paper presents the potential of bioprinting viable cell structures that could in the future present enough mechanical strength to replace a human organ, such as a meniscus. There are still limitations regarding the ink and the printing process, but we are confident that these problems will soon be solvable.

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Xia, Ming Xu, Jian Guo Li et Zhong Yun Fan. « Grain Refining through Semisolid Processing ». Solid State Phenomena 217-218 (septembre 2014) : 431–35. http://dx.doi.org/10.4028/www.scientific.net/ssp.217-218.431.

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Semisolid process can be used as grain refining method to replace conventional chemical grain refining approach. Typical semisolid slurry making techniques were introduced in the paper as potential semisolid grain refining methods. The temperature and morphology control for grain refining through semisolid process were enhanced to achieve fine particle size and large particle number rather than spheroidal particle shape or low viscosity of the slurry comparing with conventional rheo-forming process. The grain refinement effect was demonstrated by a 40 mm cylinder casting of AZ31 alloy.

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