Small aircraft infrared radiation measurements supporting the engine airframe aero-thermal integration

© 2018 Budapest University of Technology and Economics. All rights reserved. The large, EU Supported ESPOSA (Efficient Systems and propulsion for Small Aircraft) project has developed new small gas turbines for small aircraft. One of the important tasks was the engine - airframe aero-thermal radiation integration that included task of minimizing the infrared radiation of the small aircraft, too. This paper discusses the factors influencing on the aircraft infrared radiation, its possible simulation and measurements and introduces the results of small aircraft infrared radiation measurements. The temperature of aircraft hot parts heated by engines were determined for validation of methodology developed and applied to engine - aircraft thermal integration

Electrochemical migration of Ag in Na2SO4 environment

The effect of sulphate ion concentration on electrochemical migration (ECM) of silver was investigated by applying an in-situ optical and electrical inspection system. It was found that dendrites grow not only in an electrolyte solution with low sulphate ion concentration but also in electrolytes with medium and high or even saturated sulphate ion concentrations. According to the Mean-Time-To-Failure (MTTF) values, the migration susceptibility was decreased with the increase of sulphate ion concentration in case of low and medium concentration levels. However, the ECM susceptibility was increased at saturated concentration level

Electrochemical migration of Cu and Sn in Na2SO4 environment

The effect of Na2SO4 concentration on electrochemical migration (ECM) of copper and tin was investigated applying an in-situ optical and real-time electrical inspection system. According to the Mean-Time-To-Failure (MTTF) values, the ECM susceptibility of copper has increased at low concentration levels. However, the ECM susceptibility of copper has decreased at the medium and stopped at the high and even saturated concentration levels. On the other hand, the ECM susceptibility of tin has increased at low levels. Afterwards the ECM ability of tin was hindered and even stopped at medium level. Interestingly, the ECM susceptibility of tin was reappeared at high concentration levels

Wetting of Different Lead Free Solder Alloys During Vapour Phase Soldering

In this paper the wetting properties of lead free solder alloys were investigated on different printed circuit boards (PCB) during Vapour Phase Soldering (VPS), which is an alternative reflow method with non-conventional heat-transfer mechanism. Our motivation was to investigate the phenomenon on PCBs with different thermal capacities, with different heating power and with different solder alloys. The aim of the research is to clear the relations between the thermal capacities of the) PCBs and the spreading of the solder on it, and to investigate the effect of the change of heating power on the solder spreading during VPS. In addition, the impact of the VPS on different solder alloys and the performance of the VPS machine in the wake of the contact angle quality was investigated. Findings show that the thickness of the PCB is not affecting significantly the spread and the wetting. The composition of the alloy, the paste, and the heating power points to observable differences in the final result

Reversible redox chemistry of anionic imidazole-2-thione-fused 1,4-dihydro-1,4-diphosphinines

Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) appliesAnionic 1,4-dihydro-1,4-diphosphinines were synthesized from tricyclic 1,4-diphosphinines and isolated as blue powdery salts M[2a–2c]. Reaction of solutions of these monoanions with iodomethane led to P-methylated compounds 3a–3c. An oxidation/reduction cycle was examined, starting from solutions of K[2a] via P–P coupled product 4a and back to K[2a], and the recyclability and redox chemistry of this cycle were confirmed by experimental and simulated cyclic voltammetry analysis, which is proposed as a potential 2-electron cathode for rechargeable cells. TD-DFT studies were used to examine species that might be involved in the process.Ye

High p_T Spectra of Identified Particles Produced in Pb+Pb Collisions at 158GeV/nucleon Beam Energy

Transverse momentum spectra of pi^{+/-}, p, pbar, K^{+/-}, K^0_s and Lambda at midrapidity were measured at high p_T in Pb+Pb collisions at 158GeV/nucleon beam energy by the NA49 experiment. Particle yield ratios (p/pi, K/pi and Lambda/K^0_s) show an enhancement of the baryon/meson ratio for p_T>2GeV/c. The nuclear modification factor R_{CP} is extracted and compared to RHIC measurements and pQCD calculations.Comment: Quark Matter 2005 parallel section proceeding