WIRELESS power transmission, RAPID prototyping, RADIO frequency, GOLD coatings, and STAINLESS steel
This article presents an electromagnetically powered stent designed for hyperthermia treatment of in-stent restenosis. The stent device based on medical-grade stainless steel serves as a radio frequency (RF) inductive receiver to produce mild heating wirelessly through resonant-coupling power transfer, while acting as a mechanical scaffold inside an artery similar to commercial stents. The device and its custom transmitter are prototyped and optimized to show efficient wireless power transfer and stent heating through in vitro tests. The inductive stent with its helical pattern is gold coated to achieve a $3.5\times $ higher quality ($Q$) factor, improving heating performance of the device. The combinational use of independent resonant antennas with the power antenna is found to significantly boost stent temperature by up to 96% with an intermediate tissue layer. Upon matching the frequencies at which the $Q$ factors of the inductive stent, power antenna, and booster antenna are peaked, the stent excited through 10 mm-thick tissue exhibits a temperature increase of 18 °C, well over a necessary level for targeted hyperthermia treatment. The prototype achieves heating efficiencies (HEs) of 15.5–3.2 °C/W with a tissue thickness of 5–15 mm. These results indicate that the proposed resonant-heating stent system with the prototyped transmitter is promising for further development toward its clinical application. [ABSTRACT FROM AUTHOR]
IEEE Transactions on Power Electronics. Sep2019, Vol. 34 Issue 9, p8715-8723. 9p.
RAPID prototyping, CURRENT-voltage characteristics, and FEEDBACK (Electronics)
Using a photovoltaic (PV) emulator (PVE) simplifies the testing of the PV generation system. However, conventional controllers used for PVEs suffer from oscillating output voltage, requiring a high number of iterations, or being too complex to be implemented. This paper proposes a controller based on a resistance feedback control strategy that produces a stable and fast converging operating point for the PVE. The resistance feedback control strategy requires a new type of PV model, which is the current–resistance (I–R) PV model. This model is computed using a binary search method at a fast convergence rate. It is combined with a closed-loop buck converter using a proportional-integral controller to form the resistance feedback control strategy. The PVE's controller is implemented into dSPACE ds1104 hardware platform for experimental validation. The acquired experimental results show that the proposed PVE is able to follow the current–voltage characteristic of the PV module accurately. In addition, the PVE's efficiency is more than 90% under maximum power point operation. The transient response of the proposed PVE is similar to the PV panel during irradiance changes. [ABSTRACT FROM AUTHOR]
design, utopia, alteration, prototyping, progetto, and alterazione
The purpose of this paper is to re-explore the relationship between utopia and architecture, trying first and foremost to challenge the way utopia has been conceived by architectural thought: i.e., as the prefiguration of a future seen as an ‘otherness’ distinct from the present, as far as the totality of its spatial, social, and political dimensions are concerned. Such vision – as we will argue – turns out to be deeply linked to a design logic of ‘projection’ and ‘prescription’; this, however, is not the only possible logic of design. Through a reflection upon some contemporary architectural practices, we will try to highlight a new horizon for design action, in which even utopia abandons its traditional ‘projective’ role and takes on a new meaning: rather than being the non-place of a possible future, utopia stands for what doesn’t have place in the present but can emerge from its alteration. Such notion of utopia as a form of ‘situated critique’, in a concrete space and time, helps to dig more deeply into the political potential of many contemporary forms of architectural and urban design. Il proposito di questo contributo è tornare a esplorare la relazione tra utopia e architettura, cercando innanzitutto di mettere in questione il modo in cui l’utopia è stata concepita tradizionalmente nel pensiero architettonico: vale a dire, come la prefigurazione di un futuro concepito come alterità rispetto al presente, nella totalità delle sue dimensioni spaziali, sociali e politiche. Tale visione - come si cercherà di illustrare - è intimamente legata a una certa logica “proiettiva” e “prescrittiva” che, tuttavia, non è l’unica logica possibile del progetto. Attraverso una riflessione su alcuni modi del progetto di architettura contemporaneo, si cercherà infatti di mettere in evidenza una nuova logica progettuale, in cui anche l’utopia abbandona il suo carattere proiettivo tradizionale per acquisire un nuovo senso: non più il non-luogo di un futuro possibile, bensì ciò che non ha luogo nel presente e che può tuttavia emergere dalla sua alterazione. Questa nozione di utopia come “critica situata” concretamente in uno spazio e in un tempo aiuta a comprendere più in profondità il potenziale politico di molte delle forme contemporanee di progetto architettonico e urbano.