Metal Alloys for Filaments in 3D Fusion Filament Modelling Printing Process

The paper presents experimental research regarding the application of specific low melting metals in the FDM process. Previous trends in the transfer of the filament from the spool to the hot-end showed that the filament undergoes specific mechanical stress during the transfer. To achieve an appropriate transfer the filament should prove stiffness and resistance to the mechanical actions of the transfer wheels. At the same time, the entrance to the hot-end creates specific resistance to the movement of the filament, and the filament undergoes important deformations. The experimental research used three materials characterized by melting temperature below 260oC: Sn-58Bi, Sn-9Zn, and Sn-3.5Ag. Sn-58Bi showed a yield stress above 50 MPa, but very low extension during the tensile test. Sn-9Zn exhibited a yield stress above 30 MPa, and about double the extension during the tensile test. Sn-3.5Ag displayed a yield stress above 25 MPa, and extension in excess of 8%. The analysis of the surface was performed, revealing that the increase of the yield stress influenced the appearance of specific prints given by the transfer wheels. The deepest prints were measured for Sn-3.5Ag and they were maximum 100 μm. The other two materials were stiffer and the prints have depths below 50 μm. According to the obtained results, each of the tested materials can be an appropriate solution to filament use for the FDM 3D printing process

Microwave Heating of Cordierite Ceramic Substrate for After Treatment Systems

Selective catalyst reduction is one of the most affordable and successful technologies aimed at reducing NOx emissions from diesel engines. However, the reduction process can be achieved if a certain temperature is reached for the ceramic substrate of the catalytic core. The required temperatures for catalytic reaction vary from 2500 C to 4500 C depending on the technology applied in the catalytic processes. This paper aims at presenting preliminary research in microwave cordierite heating, which is a type of magnesium aluminium silicate used as ceramic honeycomb substrate (catalyst monolith) in the after treatment system in the automotive industry. The research focused on testing the Mg2Al4Si5O18 composite material (cordierite) for different microwave heating regimes in order to establish the level of microwave power required for fast heating. This application will be subject for the further development of new MW-SCR after treatment systems in order to reduce the NOx emissions at cold start engine or low operating regimes of non-road mobile machinery engines. The ceramic composite material was heated for 5 levels of microwave power, from 600 W to 1400 W, using a 6 kW microwave generator coupled with a matching load impedance tuner, and the temperatures were recorded using an IR pyrometer

On the origin of the reactor antineutrino anomalies in light of a new summation model with parameterized β−\beta^{-} transitions

We investigate the possible origins of the norm and shape reactor antineutrino anomalies in the framework of a summation model (SM) where $\beta^{-}$ transitions are simulated by a phenomenological Gamow-Teller $\beta$-decay strength model. The general trends of the discrepancies to the Huber-Mueller model on the antineutrino side can be reproduced both in norm and shape. From the exact electron-antineutrino correspondence of the SM model, we predict similar distortions in the electron spectra, suggesting that biases on the reference fission-electron spectra could be at the origin of the anomalies

Three-level stencil alignment fabrication of a high-k gate stack organic thin film transistor

In this work a high-k double-gate pentacene field-effect transistor architecture is presented. The devices are fabricated on a flexible polyimide substrate by three aligned levels of stencil lithography combined with standard photolithography. ALD-deposited high-k HfO2 and parylene D device passivation, together with Pt top-gate deposition provide very good electrostatic control of the channel, showing low leakage current and improved subthreshold. The ION/IOFF ratio is of the order of 106 and the IOFF lower than 0.1 pA/μm. We also report a comparison of the normal, FET-like (VD 0) modes of the p-OFET. We find a higher current drive in the reverse diode-like mode compared to normal FET-like mode. The reverse mode has clearly defined OFF and ON states versus the drain voltage and non-saturated output characteristics, which makes it suitable for the use in RF and analog applications of OFETs

Diffusion-engineered quasiparticle multiplication for STJ single photon detectors

We have designed a diffusion-engineered, singlephoton spectrometer in the optical-UV range using a superconducting tunnel junction. The optical photon is absorbed in a Ta film and creates excess quasiparticles. These trap into an Al tunnel junction. Internal charge multiplication is achieved with backtunneling, which occurs when the residence time of the quasiparticles near the junction is longer than the tunneling time. The collected charge is a multiple of the initially created charge. We implement backtunneling by geometrically constricting the outflow of quasiparticles, with a narrow lead. The outdiffusion time is set by the geometry of the narrow lead. Our geometry optimizes the energy resolution and count rate, while reducing the heating and noise seen with much longer confinement time. Long confinement times produce excess heating and noise, as we observed previously with quasiparticle confinement achieved via bandgap engineering

Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor

We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92±0.61±0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections

Double-gate pentacene thin-film transistor with improved control in sub-threshold region

In this work double-gate pentacene TFT architecture is proposed and experimentally investigated. The devices are fabricated on a polyimide substrate based on a process that combines three levels of stencil lithography with standard photolithography. Similarly to the operation of a conventional double-gate silicon FET, the top-gate bias modulates the threshold voltage of the bottom-gate transistor and significantly improves the transistor sub-threshold swing and leakage current. Moreover, the double gate TFT shows good promise for the enhancement of I-ON/I-OFF, especially by the control of I-OFF in devices with poor top interfaces. (C) 2010 Elsevier Ltd. All rights reserved

Sub-100 nm-scale Aluminum Nanowires by Stencil Lithography: Fabrication and Characterization

We present the fabrication process and electrical characterization of sub-100 nm scale Al nanowires (NWs) fabricated by stencil lithography (SL). We use a stencil with sub- 100 nm wide nanoslits patterned by focused ion beam (FIB) milling. The stencil is aligned and clamped onto a substrate containing predefined electrical contacts. Then a 60 nm-thick layer of Aluminum (Al) is deposited through the stencil producing NWs with lengths of ~1, 2 and 5 μm and widths down to 65 nm. The NWs show an ohmic behavior with values varying from 30 Ω up to 300 Ω, depending on the dimensions of the structures. We have extracted a resistivity for the Al NWs of ~10 x 10-8 Ωm. We also show that stencils can be cleaned and reused, proving that SL is a cost-efficient and scalable manufacturing method for the direct fabrication of metallic NWs on a full wafer scale