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Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Acier, Steel, Acero, Conception, Design, Diseño, Gestaltung, Propriété mécanique, Mechanical properties, Propiedad mecánica, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Combinatorial alloy design, Fe-Mn-Al-C steel, Steels, and Structural alloys

We introduce a new experimental approach to the compositional and thermo-mechanical design and rapid maturation of bulk structural materials. This method, termed rapid alloy prototyping (RAP), is based on semi-continuous high throughput bulk casting, rolling, heat treatment and sample preparation techniques. 45 Material conditions, i.e. 5 alloys with systematically varied compositions, each modified by 9 different ageing treatments, were produced and investigated within 35 h. This accelerated screening of the tensile, hardness and microstructural properties as a function of chemical and thermo-mechanical parameters allows the highly efficient and knowledge-based design of bulk structural alloys. The efficiency of the approach was demonstrated on a group of Fe―30Mn―1.2C―xAl steels which exhibit a wide spectrum of structural and mechanical characteristics, depending on the respective Al concentration. High amounts of Al addition (>8 wt.%) resulted in pronounced strengthening, while low concentrations (<2 wt.%) led to embrittlement of the material during ageing.

Analytical chemistry, Chimie analytique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie analytique, Analytical chemistry, Généralités, appareillage, General, instrumentation, Mécanique fluide, Fluid mechanics, Mecánica flúido, Amélioration, Improvement, Mejora, Analyse chimique, Chemical analysis, Análisis químico, Application, Aplicación, Choix, Choice, Elección, Conception, Design, Diseño, Dispositif, Device, Dispositivo, Haute pression, High pressure, Alta presión, Haute température, High temperature, Alta temperatura, Limitation, Limitación, Microfluidique, Microfluidics, Microfluidic, Moule, Mold, Molde, Méthode, Method, Método, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Qualité, Quality, Calidad, Robustesse, Robustness, Robustez, Réseau (arrangement), Array, Red, Styrène polymère, Styrene polymer, and Estireno polímero

Microfluidic cell-based systems have enabled the study of cellular phenomena with improved spatiotemporal control of the microenvironment and at increased throughput. While poly(dimethylsiloxane) (PDMS) has emerged as the most popular material in microfluidics research, it has specific limitations that prevent microfluidic platforms from achieving their full potential. We present here a complete process, ranging from mold design to embossing and bonding, that describes the fabrication of polystyrene (PS) microfluidic devices with simllar cost and time expenditures as PDMS-based devices. Emphasis was placed on creating methods that can compete with PDMS fabrication methods in terms of robustness, complexity, and time requirements. To achieve this goal, several improvements were made to remove critical bottlenecks in existing PS embossing methods. First, traditional lithographic techniques were adapted to fabricate bulk epoxy molds capable of resisting high temperatures and pressures. Second, a method was developed to emboss through-holes in a PS layer, enabling creation of large arrays of independent microfluidic systems on a single device without need to manually create access ports. Third, thermal bonding of PS layers was optimized in order to achieve quality bonding over large arrays of microsystems. The choice of materials and methods was validated for biological function in two different cell-based applications to demonstrate the versatility of our streamlined fabrication process.

Nuclear physics, Physique nucléaire, Plasma physics, Physique des plasmas, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Physique des gaz, des plasmas et des decharges electriques, Physics of gases, plasmas and electric discharges, Physique des plasmas et décharges électriques, Physics of plasmas and electric discharges, Confinement magnétique et équilibre, Magnetic confinement and equilibrium, Tokamaks, Conception, Design, Confinement magnétique, Magnetic confinement, Etude théorique, Theoretical study, Logiciel, Computer software, Modèle mathématique, Mathematical models, Modélisation, Modelling, Plasma confiné, Confined plasma, Plasma confinado, Système commande, Control systems, Sécurité, Safety, Tokamak ITER, ITER tokamak, 5255F, Hardware-in-the-loop (HIL) simulations, ITER, model-based design, and rapid prototyping

The ITER tokamak (Latin for the way) is the next step toward the realization of electricity-producing fusion power plants, since it has been designed to reach the plasma burning condition. The Central Safety System for Nuclear Risk (CSS) is the control system in charge to assure nuclear safety for the ITER plant, the personnel, and the environment. Since the CSS is a critical safety system, its validation and commissioning play an important role, and the required level of reliability must be demonstrated. In such a scenario, it is strongly recommended to use modeling and simulation tools since the early design phase. Indeed, mathematical models will help in the definition of the control system requirements. These models can be used for the rapid prototyping of the safety system, and hardware-in-the-loop (HIL) simulations can be performed to assess the performance of the control hardware against a plant simulator. This paper introduces the methodology and the software/hardware architecture used to develop both a CSS prototype and a ITER plant model suitable for the test and validation of this prototype.

Analytical chemistry, Chimie analytique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie analytique, Analytical chemistry, Généralités, appareillage, General, instrumentation, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biochimie analytique, structurale et metabolique, Analytical, structural and metabolic biochemistry, Biochimie analytique: généralités, techniques, appareillages, Analytical biochemistry: general aspects, technics, instrumentation, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Aminoacide, Aminoacid, Aminoácido, Conception miniaturisée, Miniaturized design, Concepción miniaturizada, Conception, Design, Diseño, DNA, Electrophorèse capillaire, Capillary electrophoresis, Electroforesis capilar, Electrophorèse, Electrophoresis, Electroforesis, Fabrication, Manufacturing, Fabricación, Mastic base élastomère, Elastomeric sealant, Masilla base elastomer, Microfluide, Microfluid, Microfluido, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Siloxane(diméthyl) polymère, Dimethylsiloxane polymer, Siloxano(dimetil) polímero, Structure microscopique, Microscopic structure, Estructura microscópica, Tube capillaire, Capillary tube, and Tubo capilar

This paper describes a procedure that makes it possible to design and fabricate (including sealing) microfluidic systems in an elastomeric material-poly(dimethylsiloxane) (PDMS)-in less than 24 h. A network of microfluidic channels (with width >20 μm) is designed in a CAD program. This design is converted into a transparency by a high-resolution printer; this transparency is used as a mask in photolithography to create a master in positive relief photoresist. PDMS cast against the master yields a polymeric replica containing a network of channels. The surface of this replica, and that of a flat slab of PDMS, are oxidized in an oxygen plasma. These oxidized surfaces seal tightly and irreversibly when brought into conformal contact. Oxidized PDMS also seals irreversibly to other materials used in microfluidic systems, such as glass, silicon, silicon oxide, and oxidized polystyrene; a number of substrates for devices are, therefore, practical options. Oxidation of the PDMS has the additional advantage that it yields channels whose walls are negatively charged when in contact with neutral and basic aqueous solutions; these channels support electroosmotic pumping and can be filled easily with liquids with high surface energies (especially water). The performance of microfluidic systems prepared using this rapid prototyping technique has been evaluated by fabricating a miniaturized capillary electrophoresis system. Amino acids, charge ladders of positively and negatively charged proteins, and DNA fragments were separated in aqueous solutions with this system with resolution comparable to that obtained using fused silica capillaries.

Biomedical engineering, Génie biomédical, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Maladies du système ostéoarticulaire. Traitement orthopédique, Diseases of the osteoarticular system. Orthopedic treatment, Locomotion, Locomoción, Accumulation énergie, Energy storage, Acumulación energía, Allure, Gait, Marcha, Amputation, Amputación, Biomécanique, Biomechanics, Biomecánica, Conception, Design, Diseño, Fabrication, Manufacturing, Fabricación, Frittage laser sélectif, Selective laser sintering, Sinterizacion laser selectiva, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Homme, Human, Hombre, Marche à pied, Walking, Caminata, Pied, Foot, Pie, Prothèse, Prosthesis, Prótesis, Prototypage rapide, Rapid prototyping, Prototipificación rápida, amputee, design, gait, and rapid prototyping

Proper selection of prosthetic foot-ankle components with appropriate design characteristics is critical for successful amputee rehabilitation. Elastic energy storage and return (ESAR) feet have been developed in an effort to improve amputee gait. However, the clinical efficacy of ESAR feet has been inconsistent, which could be due to inappropriate stiffness levels prescribed for a given amputee. Although a number of studies have analyzed the effect of ESAR feet on gait performance, the relationships between the stiffness characteristics and gait performance are not well understood A challenge to understanding these relationships is the inability of current manufacturing techniques to easily generate feet with varying stiffness levels. The objective of this study was to develop a rapid prototyping framework using selective laser sintering (SLS) for the creation of prosthetic feet that can be used as a means to quantify the influence of varying foot stiffness on transtibial amputee walking. The framework successfully duplicated the stiffness characteristics of a commercial carbon fiber ESAR foot. The feet were mechanically tested and an experimental case study was performed to verify that the locomotor characteristics of the amputee's gait were the same when walking with the carbon fiber ESAR and SLS designs. Three-dimensional ground reaction force, kinematic, and kinetic quantities were measured while the subject walked at 1.2 m/s. The SLS foot was able to replicate the mechanical loading response and locomotor patterns of the ESAR foot within ± 2 standard deviations. This validated the current framework as a means to fabricate SLS-based ESAR prosthetic feet. Future work will be directed at creating feet with a range of stiffness levels to investigate appropriate prescription criteria.

Aeronautics astronautics, Aéronautique, astronautique, Mechanical engineering, Génie mécanique, Mechanics acoustics, Mécanique et acoustique, Transportation, Transports, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Appareillage et mesures, Instrumentation for fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Aérodynamique, Aerodynamics, Aérodynamique, Aerodynamics, Conception, Design, Essai soufflerie, Wind tunnel test, Ensayo túnel aerodinámico, Essai sur modèle, Model test, Ensayo sobre modelo, Profil aérodynamique, Airfoils, Prototypage rapide, Rapid prototyping, Prototipificación rápida, and 4785G

Nowadays, rapid manufacturing techniques have opened a new era in aerospace industry. Wind-tunnel testing models have the most application in this industry, and different manufacturing techniques are used for production purposes. For the purpose of aerodynamics experiments, a number of different testing models may be needed to be manufactured. Airfoils are such parts that are complex and time consuming from a manufacturing point of view. At present, a new manufacturing technique has facilitated manufactures with a complex geometry, and it is now possible to replace traditional methods by this technology. In this research an airfoil model, which belongs to a missile, has been manufactured using a three-dimensional printing technology, and has been compared with a model which has been manufactured using traditional methods. The comparison is made from such aspects as the surface quality, dimensional accuracy and aerodynamics coefficients. Results reveal difference between the fabrication airfoil and the metal model due to the fact that the fabrication airfoil is different with respect to the surface quality and dimensional accuracy. Therefore, a significant difference in some of the aerodynamics coefficients can be observed. It can be concluded from this research that, the manufactured models using a three-dimensional printing method can be used for primary tests, being less expensive and requiring significantly less time to build.

Mechanical engineering, Génie mécanique, Computer science, Informatique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Informatique; automatique theorique; systemes, Computer science; control theory; systems, Logiciel, Software, Conception assistée, Computer aided design, Electronique, Electronics, Matériel informatique, Hardware, Ordinateurs, microordinateurs, Computers, microcomputers, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Conception industrielle, planification, organisation, sécurité, Industrial design, planning, organization, safety, Architecture système, System architecture, Arquitectura sistema, Conception, Design, Elaboration rapide prototype, Rapid prototyping, Encapsulation, Ingénierie concurrente, Concurrent engineering, Mobilité, Mobility, Movilidad, Méthodologie, Methodology, Metodología, Ordinateur, Computers, Préparation gamme fabrication, Process planning, Preparación serie fabricación, Spécification, Specifications, Distributed design, Mobile computers, Navigator, and Wearable computers

At Carnegie Mellon, we have designed and manufactured three generations of wearable, mobile computers. Each new generation of wearable computer has been designed within approximately one semester by an interdisciplinary design class taught at the Engineering Design Research Center (EDRC). Over the semesters that the course has been taught, an interdisciplinary concurrent design methodology has evolved. In this paper, we briefly present the design process for the Navigator, the third generation of wearable computers. We use this process to illustrate the needs of a multidisciplinary design team, to anticipate the needs of a distributed design team using a novel manufacturing process, and to reflect on the interplay between the practice of design and the evolution of our design methods.