1,721,052 research outputs found
Energy Harvesting and Scavenging
No full textThe articles in this special issue cover recent advances in energy-harvesting and energy-scavenging systems with a focus on numerous "renewable" transducer technologies as well as emerging applications. energy-harvesting technologies are fundamental in enabling the realization of "zero-power" wireless sensors and implementing the Internet-of-Things (IoT) and machine-to-machine (M2M) communication. Their increasing utilization in low-power and power-efficient sensors and electronics could potentially find application in numerous critical areas ranging from health, agricultural, structural health monitoring to logistics, localization, and security. Energy-harvesting devices, including solar panels, piezoelectric devices, thermocouples, and RF energy scavengers, can dramatically extend the operating lifetime of nodes in wireless sensor networks (WSNs). Furthermore, this technology enables a completely battery-less operation and reduces the operation cost of WSNs, which is mainly due to battery replacement, thus making it very important for a sustainable "near-perpetual" WSN operability.© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works
State-of-the-Art Inkjet-Printed Metal-Insulator-Metal (MIM) Capacitors on Silicon Substrate
No full textVertically-integrated metal-insulator-metal (MIM) capacitors on silicon are demonstrated for the first time utilizing an entirely additive RF-specific inkjet-printing process. The inkjet-printed MIM capacitors demonstrate a high capacitance per unit area of up to 33 pF/mm2 by utilizing novel dielectric inks, while achieving quality factors (Q) up to 25 and self-resonant frequencies (SRFs) above 1 GHz. Measurements of dielectric permittivity, leakage current, voltage breakdown, and fabrication repeatability are presented confirming the high-performance operation of the printed MIM capacitors
Development of Low Cost, Wireless, Inkjet Printed Microfluidic RF Systems and Devices for Sensing or Tunable Electronics
No full textEnergy-Efficient Harmonic Transponder Based on On-Off Keying Modulation for Both Identification and Sensing
No full textThis paper presents a novel passive Schottky-diode frequency doubler equipped with an on-off keying (OOK) modulation port to be used in harmonic transponders for both identification and sensing applications. The amplitude modulation of the second-harmonic output signal is achieved by driving a low-frequency MOSFET, which modifies the dc impedance termination of the doubler. Since the modulation signal is applied to the gate port of the transistor, no static current is drained. A proof-of-concept prototype was manufactured and tested, operating at 1.04 GHz. An on/off ratio of 23 dB was observed in the conversion loss of the doubler for an available input power of −10 dBm. The modulation port of the circuit was excited with a square wave (fm up to 15 MHz), and the measured sidebands in the spectrum featured a good agreement with the theory. Then, the doubler was connected to a harmonic antenna system and tested in a wireless experiment for fm up to 1 MHz, showing an excellent performance. Finally, an experiment was conducted where the output signal of the doubler was modulated by a reed switch used to measure the rotational speed of an electrical motor. This work opens the door to a new class of frequency doublers, suitable for ultra low-power harmonic transponders for identification and sensing applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Novel Ultra-Lightweight Multiband Rectenna on Paper for RF Energy Harvesting in the Next Generation LTE Bands
No full textThis paper introduces a novel compact ultralightweight multiband RF energy harvester fabricated on a paper substrate. The proposed rectenna is designed to operate in all recently released LTE bands (range 0.79-0.96 GHz; 1.71-2.17 GHz; and 2.5-2.69 GHz). High compactness and ease of integration between antenna and rectifier are achieved by using a topology of nested annular slots. The proposed rectifier features an RF-to-dc conversion efficiency in the range of 5%-16% for an available input power of -20 dBm in all bands of interest, which increases up to 11%-30% at -15 dBm. The rectenna has been finally tested both in laboratory and in realistic scenarios featuring a superior performance to other state-of-the-art RF harvesters on flexible substrates
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
