323,830 research outputs found
Legacy of Excellence: Honoring the Leadership of Ross Stone in Editorial, Industry and Science
No full textWith his extensive experience of over 45 years in the field, Ross Stone was a towering figure and a guiding light in the Antennas and Propagation and Radio Science community. Throughout his career, he made significant contributions to industry, consulting, and research in antennas, propagation, and related technologies. Renowned for his exceptional skills and altruistic nature in supporting and fostering new initiatives, Ross became a key figure in major international societies and networks. His involvement with the IEEE Antennas and Propagation Society (AP-S), the International Union of Radio Science (URSI), and the European Association on Antennas and Propagation (EuRAAP) was profoundly influential. His active participation and leadership within these organizations was driven by his commitment to advancing the field and fostering and serving global scientific and technical communities. Through his roles, Ross not only contributed to the technical advancement of antennas and propagation but also played a pivotal role in bridging gaps between different scientific communities and enhancing international collaboration
MACI Sandwich Technique With Autologous Bone Graft
No full textBackground: Osteochondral lesions of the knee are difficult to manage. Such lesions can be effectively treated with the matrix-induced autologous chondrocyte implantation (MACI) “sandwich” technique using autologous chondrocytes on porcine collagen membrane in conjuction with autologous cancellous bone grafting (ABG). Few studies have examined this technique to restore the osteochondral unit. Indications: The MACI “Sandwich” procedure is indicated when osteochondral lesions are larger than 2 cm 2 in size and deeper than 8 to 10 mm, with symptoms consistent with the location of the lesion. Technique Description: The chondral defect is radically debrided back to healthy bone and cartilage tissue. The base of the bony cavity is drilled to enhance the vascular supply and promote healing. Next, the bony cavity is prepared to slightly undermine the subchondral bone surface around the articular margins, with the depth of the cavity wider than the opening, similar to a dental amalgam. The autologous cancellous bone is subsequently morselized and impacted up to the level of the native subchondral bone plate. The first MACI membrane with the cells facing up is placed directly onto the bone graft site and compressed with a neural patty. The neural patty is removed, and the second MACI membrane is then placed with the cells facing down. The edges are then micro-sutured to ensure stability. Results: The “sandwich” technique has superior survival rates compared with autologous bone grafting alone, with patients reporting decreased pain, improved function, and high satisfaction scores over a mid-term to long-term follow-up. Discussion/Conclusion: The MACI “sandwich” technique is an effective surgical intervention to restore the osteochondral unit and preserve the patient's native knee joint. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication
A Cloaking Metamaterial Based on an Inhomogeneous Linear Field Transformation
No full textA new type of bianisotropic metamaterial is theoretically investigated on the basis of a linear inhomogeneous field transformation applied to an arbitrary free-space Maxwellian field. This transformation does not include any space compression as predicted by transformation optics, and consists of a linear combination with space-dependent coefficients of the electric and magnetic incident fields. Duality conditions are applied to select an appropriate shape of the constituent dyads, thus resulting in a metamaterial completely defined by two real differentiable functions of space sigma and eta. When these functions satisfy the condition sigma(2) + eta(2) on the medium contour, the medium becomes globally lossless, and when imposing sigma = 0 and eta = 1 at the same boundary, the medium does not scatter for any arbitrary incident field, that is, it becomes invisible. When an additional internal boundary is introduced with boundary conditions sigma = 0 and eta = 0, the medium becomes a perfect cloak. Explicit analytical results are given for an invisible sphere and for a spherical cloak to provide additional physical insight
The European School of Antennas: Structure, results and perspectives
No full textThe European School of Antennas (ESoA) is a geographically distributed nonprofit post-graduate school on antennas, propagation, and relevant applications. The ESoA courses are distributed in the most accredited European research centers of antennas and wireless systems. In the first three year of life, the ESoA courses involved about 680 students and more than 150 different teachers, mostly university professors. This paper presents the structure of the school, the results obtained since its founding, and its future development and perspectives
Closed form expressions for the modal dispersion equations and for the characteristic impedance of a metamaterial based gap waveguide
No full textIn a recent sequence of papers, a parallel-plate ridge gap waveguide has been introduced, that consists of a metal ridge in a metamaterial magnetic conductor surface, covered by a metallic plate at a small height above it. The gap waveguide is relatively simple to manufacture, especially at millimetre and sub-millimetre wave frequencies when compared with other solutions. The metamaterial surface is designed to provide a frequency band where parallel-plate modes are in cut-off, thereby allowing for a confined gap wave to propagate along the ridge. In a previous work, the authors have presented an approximate analytical solution for the confined quasi-TEM dominant mode of the ridge gap waveguide, when the surrounding metamaterial surface is in the form of a bed of nails. In this study, the authors investigation continues by providing an analytical expression of the modal dispersion equation of the first higher order ridge mode and of the characteristic impedance of the dominant mode. As in the previous paper, the field problem is divided in three regions, the central region above the ridge and the two surrounding side regions above the nails. Transverse mode-matching applied to a few modes representation in each region, results in a closed form expression of the dispersion equation of the first higher order mode. After summarising the formulation for the dominant quasi-TEM mode, the dispersion equation of the first higher order mode is derived, in order to give a criterion to maximise the unimodal bandwidth. Furthermore, three different closed form expressions of the dominant mode characteristic impedance are derived and compared with approximate expressions already used in literature
Introduction [to The Routledge Handbook of Scientific Communication]
No full textThis handbook approaches the study of scientific communication from a primarily rhetorical perspective, though some chapters also contain some linguistic and narrative analysis as well. A rhetorical perspective is a form of textual analysis that focuses on the purpose(s) of a text, bearing in mind the text’s effectiveness with respect to one or more target audiences. A rhetorical perspective, like other forms of textual analysis, is informed and shaped by organizational, national, and cultural contexts. Additionally, this handbook largely considers scientific communication—communication among scientists, including, in some cases, citizen scientists who participate in the scientific process—rather than science communication—communication between scientists and nonscientists. Finally, this handbook considers science as the largely inductive, experimental process that is characterized in general by partition, measurement, and quantitative analysis and that has evolved since the Scientific Revolution, centered mostly in Europe, in the late 1600s. It is fair to say that today no rhetoric defines our lives more than scientific rhetoric. As the form of rhetoric most commonly perceived as a source of knowledge, reality, and truth, scientific rhetoric occupies a dominant, privileged position among the types of rhetorics that shape human experience. Scientific rhetoric creates and consumes vast amounts of discursive energy for issues from the monumental to the mundane. Given its enormous epistemological and ontological potential, then, scientific rhetoric deserves careful, continual analysis from scholars of rhetoric and communication. Additionally, scientists need to be aware of the powerful role that scientific rhetoric plays in our culture and attend to their work with this discourse assiduously and ethically
A complete set of Linear-Phase basis functions for scatterers with flat faces and for planar apertures
No full textEntire-domain basis functions are introduced for the analysis of scattering from bodies with flat portions, and of radiation from planar apertures; they are defined via the application of the sampling theorem of Shannon. These basis functions are particularly convenient for polygonal contours; however, arbitrary contours can be treated in the same framework with a very minor pre-processing time. A non-redundant set of basis functions is determined a priori by explicit approximate formulas either for currents and for radiated field. Numerical results are presented to shown the accuracy of the method. © 2010 IEEE
A closed-form conversion from spherical-wave- to complex-point-source-expansion
No full textA simple closed-form expression for a complex point source (CPS) beam expansion of an arbitrary electromagnetic field is derived. The expansion process consists of two steps: first, a particular form of the equivalence principle is applied to a sphere enclosing the real sources, and a continuous equivalent electric current distribution is obtained in terms of spherical waves (SW); then, the continuous current is extended to complex space and its SW components are properly filtered and sampled to generate the discrete set of CPS. The final result is a compact finite series representation suitable for arbitrary radiated fields, and particularly efficient when the source is highly directional and/or the observation domain is limited to a given angular sector. The robustness of the process is demonstrated by showing its connection with the singular value decomposition of the radiation operator from a complex sphere
G. Tessuto. Blogging about health: Investigating interpersonal language for discourse features of stance and engagement. In S. Maci / M. McGlashan (ed.), Critical Discourse Analysis and the New Normal.
No full textEM Metasurfaces [Guest Editorial]
No full textMetasurfaces (MTSs) [1], [2], [3], [4], [5] are the surface equivalent of metamaterials (MTMs): artificial materials composed of subwavelength inclusions embedded in a host medium tailored to exhibit unconventional electromagnetic (EM) properties. In contrast to MTMs, which are characterized in terms of homogenized material parameters, the EM responses of MTSs are often characterized by homogenized boundary conditions (BCs). MTSs can be designed to exhibit abrupt amplitude and phase discontinuities to perform extreme wavefront transformations. Classical 'surface EMs' [3] took on fresh and exciting research directions with MTSs, revealing fascinating phenomena and new applications
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