There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Additive manufacturing of metallic components – Process, structure and properties

Freedom of design, mass customisation, waste minimisation and the ability to manufacture complex structures, as well as fast prototyping, are the main benefits of additive manufacturing (AM) or 3D printing. A comprehensive review of the main 3D printing methods, materials and their development in trending applications was carried out. In particular, the revolutionary applications of AM in biomedical, aerospace, buildings and protective structures were discussed. The current state of materials development, including metal alloys, polymer composites, ceramics and concrete, was presented. In addition, this paper discussed the main processing challenges with void formation, anisotropic behaviour, the limitation of computer design and layer-by-layer appearance. Overall, this paper gives an overview of 3D printing, including a survey on its benefits and drawbacks as a benchmark for future research and development.

Additive manufacturing (3D printing): A review of materials, methods, applications and challenges

This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

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Metal Additive Manufacturing: A Review

Natural structural materials are built at ambient temperature from a fairly limited selection of components. They usually comprise hard and soft phases arranged in complex hierarchical architectures, with characteristic dimensions spanning from the nanoscale to the macroscale. The resulting materials are lightweight and often display unique combinations of strength and toughness, but have proven difficult to mimic synthetically. Here, we review the common design motifs of a range of natural structural materials, and discuss the difficulties associated with the design and fabrication of synthetic structures that mimic the structural and mechanical characteristics of their natural counterparts.

Bioinspired structural materials

An efficient and systematic strategy to find the propagation constants of real, complex, and leaky modes of covered and uncovered planar multilayered isotropic/uniaxial waveguides is presented. This strategy first builds up a pole-free characteristic function and then makes use of a root-searching scheme based on an integral nature method to search for its zeros. For uncovered waveguides, the branch points of the characteristic function can be removed by introducing the upper half-space vertical wavenumber as the working variable. Examples of the efficiency, reliability, and robustness of the presented technique are given for both covered and uncovered waveguides, which sets up this technique as a very convenient CAD tool. The method is also applied to study a new and interesting problem: the evolution of the modes of a grounded dielectric waveguide when increasing the permittivity of the upper semi-infinite medium. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 73–83, 2004

Systematic and efficient root finder for computing the modal spectrum of planar layered waveguides: Original Articles

The metallic powder bed fusion (PBF) marketplace has been growing rapidly in the second decade of the twenty-first century. The technology has been incorporated into design, engineering, and manufacturing. This chapter will provide insight into the current status of the global 3D printing marketplace with emphasis on additive manufacturing activities and how they are impacting the global supply base. 3D printing will have a major influence on global supply chain logistics and traditional supply chain establishments.

The Additive Manufacturing Supply Chain

The authors apply Galerkin's method in the Hankel transform domain (HTD) is applied to the determination of the radar cross section (RCS) of stacked circular microstrip patches which can be used as either increased bandwidth microstrip antennas or dual-frequency microstrip antennas. The numerical results obtained show that the RCS values of a pair of stacked circular patches may be very different from those obtained for one patch in the absence of the other patch.

Determination of the radar cross section of stacked circular microstrip patches

A fully analytical solution for the scattering of a uniform TE polarized plane wave by an infinite periodic printed array of narrow slits is provided in this contribution. The model is based on some simplifications made on the formulas arising from a rigorous full-wave formulation. The present approach gives the topology of the transverse equivalent network as well as closed-form expressions for all its components, and overall very accurate results.

Fully analytical circuit-like approach for the TE scattering by narrow-slit printed gratings

Mediation becomes relevant nowadays as a way to manage conflicts in the workplace in a nonjudicial way, preventing costly, extensive, and unsatisfying legal procedures. This study tries to systematize the more recent research about mediation, showing the main challenges, questions, and findings. Research suggests the importance of integrating the organizational and societal context in the study of mediation, the use of efficiency, equity, and voice objectives for evaluating mediation effectiveness, and taking into account a contingency approach in mediator strategies. There is an important gap between the large development of professional practice in mediation and the few systematic studies on this topic. This paper offers a model that considers current research and practice for mediation effectiveness. This model could be used to focus the orientation of scholars, practitioners, and governments in search of new developments in the design of mediation. Future research could explore specific combinations of these dimensions to analyze sectors, organizations, or cases of mediation. La mediación: una herramienta de gestión constructiva del conflicto en el lugar de trabajo

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Francisco Medina

Papers

Systematic and efficient root finder for computing the modal spectrum of planar layered waveguides: Original Articles

The Additive Manufacturing Supply Chain

Determination of the radar cross section of stacked circular microstrip patches

Fully analytical circuit-like approach for the TE scattering by narrow-slit printed gratings

Mediation: Understanding a Constructive Conflict Management Tool in the Workplace