Interfacial properties of fibre reinforced thermo-plastics

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Mechanically reconfigurable microstrip lines loaded with stepped impedance resonators and potential applications

This paper is focused on exploring the possibilities and potential applications of microstrip transmission lines loaded with stepped impedance resonators (SIRs) etched on top of the signal strip, in a separated substrate. It is shown that if the symmetry plane of the line (a magnetic wall) is perfectly aligned with the electric wall of the SIR at the fundamental resonance, the line is transparent. However, if symmetry is somehow ruptured, a notch in the transmission coefficient appears. The notch frequency and depth can thus be mechanically controlled, and this property can be of interest for the implementation of sensors and barcodes, as it is discussed

Angular displacement and velocity sensors based on electric-LC (ELC) loaded microstrip lines

Planar microwave angular displacement and angular velocity sensors implemented in microstrip technology are proposed. The transducer element is a circularly shaped divider/combiner, whereas the sensing element is an electricLC resonator, attached to the rotating object and magnetically coupled to the circular (active) region of the transducer. The angular variables are measured by inspection of the transmission characteristics, which are modulated by the magnetic coupling between the resonator and the divider/combiner. The degree of coupling is hence sensitive to the angular position of the resonator. As compared with coplanar waveguide angular displacement and velocity sensors, the proposed microstrip sensors do not require air bridges, and the ground plane provides backside isolation

Microwave sensors based on symmetry properties of resonator-loaded transmission lines

This review paper is focused on the design of microwave sensors using symmetry properties of transmission lines loaded with symmetric resonators. The operating principle of these sensors is presented and then several prototype devices are reported, including linear and angular displacement sensors and rotation speed sensors. The main advantage of the proposed sensors is the robustness against changing environmental conditions

Biodegradation of rocket propellent waste, ammonium perchlorate

The impact of the biodegradation rate of ammonium perchlorate on the environment was studied in terms of growth, metabolic rate, and total biomass of selected animal and plant species. Brief methodology and detailed results are presented

Trayectoria hacia la jubilación: condicionantes y consecuencias

The stage about working life is the most important and significant stage because is the activity which is more realizing. Because of that, when the stage of retirement arrives, various options are open and most of them with some doubts. The main objective of this investigation is to analyze what is the vision of the workers in this stage. The established methodology is based on a qualitative analysis. The results of this study are discussed in terms of different groups: 50-55 years, 55-60 years and 60-65 years. We find diversity of perceptions of retirement based on personal experience, yet all with a common denominator: the importance of social and folkloric support. Thus a program of preparation for retirement should be approached individually and should include a theoretical part and another practice part focused on each person.La etapa de la vida laboral es una de las más importantes y significativas, ya que es la que más nos autorrealiza. El objetivo de esta investigación es analizar la percepción de la jubilación en las diferentes etapas de la vida laboral. La metodología establecida se basa en un análisis cualitativo. Los resultados del presente estudio se analizan en función de los diferentes grupos: de 50-55 años, de 55-60 años y de 60-65 años. Hallamos diversidad de percepciones de la jubilación en función de la trayectoria personal, aún así todas con un denominador común: la importancia del apoyo social y folclórico de esta etapa. Así pues, un programa de preparación a la jubilación debe ser enfocado de forma individual e incluir una parte teórica y otra más práctica dirigida a cada individuo

The Beauty of Symmetry: Common-mode rejection filters for high-speed interconnects and balanced microwave circuits

Common-mode rejection filters operating at microwave frequencies have been the subject of intensive research activity in the last decade. These filters are of interest for the suppression of common-mode noise in high-speed digital circuits, where differential signals are widely employed due to the high immunity to noise, electromagnetic interference (EMI) and crosstalk of differential-mode interconnects. These filters can also be used to improve common-mode rejection in microwave filters and circuits dealing with differential signals. Ideally, common-mode stopband filters should be transparent for the differential mode from DC up to very high frequencies (all-pass), should preserve the signal integrity for such mode, and should exhibit the widest and deepest possible rejection band for the common mode in the region of interest. Moreover, these characteristics should be achieved by means of structures with the smallest possible size. In this article, several techniques for the implementation of common-mode suppression filters in planar technology are reviewed. In all the cases, the strategy to simultaneously achieve common-mode suppression and all-pass behavior for the differential mode is based on selective mode-suppression. This selective mode suppression (either the common or the differential mode) in balanced lines is typically (although not exclusively) achieved by symmetrically loading the lines with symmetric resonant elements, opaque for the common-mode and transparent for the differential mode (common-mode suppression), or vice versa (differential-mode suppression).MINECO, Spain-TEC2013-40600-R, TEC2013-41913-PGeneralitat de Catalunya-2014SGR-15

Differential and Single-Ended Microstrip Lines Loaded with Slotted Magnetic-LC Resonators

This paper is focused on magnetic-LC (MLC) resonators, namely, slotted resonators that can be considered the complementary counterparts of the so-called electric-LC (ELC) resonators. Both resonators exhibit two symmetry planes (i.e., they are bisymmetric), one of them being an electric wall and the other a magnetic wall at the fundamental resonance. Therefore, compared to other electrically small resonators such as folded stepped impedance resonators (SIRs), split ring resonators (SRRs), and their complementary counterparts, MLC and ELC resonators exhibit a very rich phenomenology. In this paper, single-ended microstrip lines and differential microstrip lines loaded with MLC resonators are studied, and potential applications are highlighted

Selective mode suppression in microstrip differential lines by means of electric-LC (ELC) and magnetic-LC (MLC) resonators

CIMITECIn this paper, it is demonstrated that the so-called electric-LC (ELC) resonators, and their dual counterparts, the magnetic-LC (MLC) resonators, are useful for the selective suppression of either the differential or the common mode in microstrip differential lines. The key point to mode suppression is the alignment of the resonator with the electric (differential mode) or magnetic (common mode) wall of the line. It is shown that by simply rotating the resonators 90∘ we can selectively choose the suppressed mode in the vicinity of the resonator's fundamental resonance frequency. The theory is validated through full-wave electromagnetic simulation, the lumped element equivalent circuit models of the proposed structures and experimental data

Spectral signature barcodes based on S-shaped split ring resonators (S-SRRs)

In this paper, it is shown that S-shaped split ring resonators (S-SRRs) are useful particles for the implementation of spectral signature (i.e., a class of radiofrequency) barcodes based on coplanar waveguide (CPW) transmission lines loaded with such resonant elements. By virtue of its S shape, these resonators are electrically small. Hence S-SRRs are of interest for the miniaturization of the barcodes, since multiple resonators, each tuned at a different frequency, are used for encoding purposes. In particular, a 10-bit barcode occupying 1 GHz spectral bandwidth centered at 2.5 GHz, with dimensions of 9 cm2, is presented in this paper