In recent years rapid prototyping technology has been implemented in many spheres of industry, particularly the field of product development. Existing process provide the capability to rapidly produce a tangible solid part, directly from three dimensional CAD data, from a range of nonmetallic materials. In many situations the desired end product of a development cycle is a metallic object, whether a component or a tool. The development of a system capable of the direct manufacture of fully dense, metal parts is therefore seen as an important landmark in the evolution of rapid prototyping technology. A unique experimental project has been carried out to investigate the potential of laser surface cladding by pneumatic powder delivery to form the basis for such a process. A layered manufacturing part building strategy is proposed, in which laser cladding is used to deposit the near net shape of each layer. Conventional machining techniques are then used to trim each layer to the exact dimensions specified by the CAD data. A multi-kilowatt carbon dioxide laser was integrated with a four axis machine tool to create an opto-mechanical workstation on which to perform the process. A detailed study of the effects of cladding process parameters on the geometry of the deposited metal was carried out and quantitative relationships derived. These relationships are used to select process parameters appropriate to the geometry of the deposition required. A numerical method to fully describe the deposited clad geometry was developed in order that efficient cutter paths could be generated for the back machining cycle. These relationships are also used to determine the minimum size of deposited bead from which the required layer section may be machined, in order to optimise process efficiency. The application of the technique to the generation of a variety of simple geometries was investigated and the potential problems identified. A preliminary investigation into the process accuracy is made, relating specifically to the predictability of the geometry of multiple layer depositions and the distortion of parts as subsequent layers are deposited. The limits of geometrical complexity possible with the current apparatus, and the unsatisfactory build times involved, suggest that the most attractive application of this technique is as part of a hybrid process, adding a novel additive dimension to existing automated fabrication techniques.

No / This title provides a comprehensive and authoritative review on recent advancements in the application and use of composite scaffolds in tissue engineering. Chapters focus on specific tissue/organ (mostly on the structure and anatomy), the materials used for treatment, natural composite scaffolds, synthetic composite scaffolds, fabrication techniques, innovative materials and approaches for scaffolds preparation, host response to the scaffolds, challenges and future perspectives, and more. Bringing all the information together in one major reference, the authors systematically review and summarise recent research findings, thus providing an in-depth understanding of scaffold use in different body systems.

No / This title provides a comprehensive and authoritative review on recent advancements in the application and use of composite scaffolds in tissue engineering. Chapters focus on specific tissue/organ (mostly on the structure and anatomy), the materials used for treatment, natural composite scaffolds, synthetic composite scaffolds, fabrication techniques, innovative materials and approaches for scaffolds preparation, host response to the scaffolds, challenges and future perspectives, and more. Bringing all the information together in one major reference, the authors systematically review and summarise recent research findings, thus providing an in-depth understanding of scaffold use in different body systems.

Yes / Fabrication of extracellular matrix (ECM)-like scaffolds (in terms of structural-functional) is the main challenge in skin tissue engineering. Herein, inspired by macromolecular components of ECM, a novel hybrid scaffold suggested which includes silk/hyaluronan (SF/HA) bio-complex modified by PCP: [polyethylene glycol/chitosan/poly(ɛ-caprolactone)] copolymer containing collagen to differentiate human-adipose-derived stem cells into keratinocytes. In followed by, different weight ratios (wt%) of SF/HA (S1:100/0, S2:80/20, S3:50/50) were applied to study the role of SF/HA in the improvement of physicochemical and biological functions of scaffolds. Notably, the combination of electrospinning-like and freeze-drying methods was also utilized as a new method to create a coherent 3D-network. The results indicated this novel technique was led to ~8% improvement of the scaffold's ductility and ~17% decrease in mean pore diameter, compared to the freeze-drying method. Moreover, the increase of HA (>20wt%) increased porosity to 99%, however, higher tensile strength, modulus, and water absorption% were related to S2 (38.1, 0.32 MPa, 75.3%). More expression of keratinocytes along with growth pattern similar to skin was also observed on S2. This study showed control of HA content creates a microporous-environment with proper modulus and swelling%, although, the role of collagen/PCP as base biocomposite and fabrication technique was undeniable on the inductive signaling of cells. Such a scaffold can mimic skin properties and act as the growth factor through inducing keratinocytes differentiation.

La technologie MID (Molded Interconnect Device), fait de leur performance électrique, la flexibilitédans les circuits RF, le potentiel de réduire le nombre de composants, les étapes du processus et laminiaturisation du produit final, a conduit à de nouvelles contraintes à la RF (Radio Frequency) et ledomaine des micro-ondes. Composants moulés sont interconnectées avec des substratsthermoplastiques et les pistes conductrices sont injectés sur la surface. L'objectif de cette thèse estd'étudier la compatibilité de MID pour les applications RF. Les avantages de la technologie MID dansle domaine RF est exploitée pour les lignes de transmission, filtres passifs, coupleurs directionnels etantennes réalisation. La caractérisation RF de différents matériaux de substrat MID et l'étude de laperformance des composants RF ci-dessus sur la base de différentes technologies de fabrication MIDsont inclus dans la thèse. Enfin, le concept d'une étude d'amélioration de la permittivité de certainsthermoplastiques sont également étudiés. / MID (Molded Interconnect Devices) technology, owing to their electrical performance,flexibility in RF circuits, its potential to reduce the number of components, process steps andminiaturization of the final product, has led to some new constraints to the RF (RadioFrequency) and microwave domain. Molded components are interconnected withthermoplastic substrates and conductive traces are injected on the surface. The objective ofthis thesis is to study the compatibility of MIDs for RF applications. The advantages of MIDtechnology in the RF domain is exploited for transmission lines, passive filters, directionalcouplers and planar and 3D antennas realization. The RF characterization of various MIDsubstrate materials and the study of the performance of the above RF components based onvarious MID fabrication technologies are included in the thesis. Finally, an permittivityimprovement study of some thermoplastics are also studied.

La technologie MID (Molded Interconnect Device), fait de leur performance électrique, la flexibilitédans les circuits RF, le potentiel de réduire le nombre de composants, les étapes du processus et laminiaturisation du produit final, a conduit à de nouvelles contraintes à la RF (Radio Frequency) et ledomaine des micro-ondes. Composants moulés sont interconnectées avec des substratsthermoplastiques et les pistes conductrices sont injectés sur la surface. L'objectif de cette thèse estd'étudier la compatibilité de MID pour les applications RF. Les avantages de la technologie MID dansle domaine RF est exploitée pour les lignes de transmission, filtres passifs, coupleurs directionnels etantennes réalisation. La caractérisation RF de différents matériaux de substrat MID et l'étude de laperformance des composants RF ci-dessus sur la base de différentes technologies de fabrication MIDsont inclus dans la thèse. Enfin, le concept d'une étude d'amélioration de la permittivité de certainsthermoplastiques sont également étudiés. / MID (Molded Interconnect Devices) technology, owing to their electrical performance,flexibility in RF circuits, its potential to reduce the number of components, process steps andminiaturization of the final product, has led to some new constraints to the RF (RadioFrequency) and microwave domain. Molded components are interconnected withthermoplastic substrates and conductive traces are injected on the surface. The objective ofthis thesis is to study the compatibility of MIDs for RF applications. The advantages of MIDtechnology in the RF domain is exploited for transmission lines, passive filters, directionalcouplers and planar and 3D antennas realization. The RF characterization of various MIDsubstrate materials and the study of the performance of the above RF components based onvarious MID fabrication technologies are included in the thesis. Finally, an permittivityimprovement study of some thermoplastics are also studied.