Recovery of Yttrium Oxide from Titanium-Aluminium based wastes

Yttrium belongs to the rare earth elements and critical metals.Yttrium oxide is mostly used in fluoroscent lamps, production ofelectrodes, in electronic filters, lasers, superconductors and asadditives in various titanium-aluminium materials to improve theirproperties. Recovery of yttrium oxide from secondary sourcessuch as red mud, coatings from ceramic industry and phosphors isextremely important. The main aim of this study is to examine theselective recovery of yttrium oxide from Al-Ti based secondarymaterials using one combined method based mostly on leachingfor selective recovery of yttrium containing: crashing and grindingof materials, sieving, leaching of chosen fine fraction withhydrochloric acid, precipitation with oxalic acid in order to producea pure yttrium oxalate, filtration and a final thermal decompositionof yttrium oxalate. The present study summarized mostly theinfluence of different reaction parameters such as leachingtemperature, time and concentration of hydrochloric acid onyttrium dissolution from Al-Ti based secondary materials. Anincrease of dissolution time and temperature increases yttriumdissolution. An increase of pressure from an atmospheric pressureto 0.5 MPa at 150°C leads to the maximum dissolution of yttrium(about 98.6 %). The final produced yttrium oxide after thermaldecomposition of yttrium oxalate was analyzed using SEM andEDS-analysis.

Direct Measure of Rigid Body Accelerations for Wave Impact of a Planing Hull

Measurements of accelerations during wave impact of a planing hull are usually contaminated by nonhydrodynamic disturbances inherent in full-scale tests and by vibrations induced by the test model and towing carriage in towing tank tests. As a consequence, researchers have resorted to the use of electronic filters to extract rigid body hydrodynamic impact accelerations. This article first calculates the rigid body impact acceleration time histories of 2dimensional deadrise wedges impacting on a level water surface as a function of initial contact velocity, deadrise angle, and unit drop weight. It also calculates the spectral content of these time histories. It then demonstrates how the time histories, time to peak, and spectral content of these 2D wedges are distorted by the use of standard "one-way" electronic filters when processing the data. In a sense, this section of the article can be taken as a simple tutorial on the impact process. The Davidson Laboratory suggests and demonstrates the use of a rigid "free-running" model that is not rigidly connected to the towing carriage and is thus devoid of carriage-induced disturbances. This obviates the use of filters in processing the recorded data. Hence, the directly measured impact accelerations are thus rigid body hydrodynamic accelerations. These are compared with measurements made with the model rigidly attached to the carriage to demonstrate its effect on contaminating the recorded hydrodynamic signal. It is recommended that other towing tanks consider the use of this or other "free-model" test procedures to identify the possible contamination of the recorded acceleration time histories introduced by their carriage and model disturbances. It is also recommended that for those full-scale tests, where the "Standard G" method of data reduction has been applied, that a model be built and tested using the "free-model" test procedure suggested in this article. This will compare the derived rigid body accelerations with the true hydrodynamic impact accelerations as obtained in these free-model tests.

Nanoelectronic primary thermometry below 4 mK

Cooling nanoelectronic structures to millikelvin temperatures presents extreme challenges in maintaining thermal contact between the electrons in the device and an external cold bath. It is typically found that when nanoscale devices are cooled to ∼10 mK the electrons are significantly overheated. Here we report the cooling of electrons in nanoelectronic Coulomb blockade thermometers below 4 mK. The low operating temperature is attributed to an optimized design that incorporates cooling fins with a high electron–phonon coupling and on-chip electronic filters, combined with low-noise electronic measurements. By immersing a Coulomb blockade thermometer in the 3He/4He refrigerant of a dilution refrigerator, we measure a lowest electron temperature of 3.7 mK and a trend to a saturated electron temperature approaching 3 mK. This work demonstrates how nanoelectronic samples can be cooled further into the low-millikelvin range.

Analog filter diagnosis using the oscillation based method

Oscillation Based Testing (OBT) is an effective and simple solution to the testing problem of continuous time analogue electronic filters. In this paper, diagnosis based on OBT is described for the first time. It will be referred to as OBD. A fault dictionary is created and used to perform diagnosis with artificial neural networks (ANNs) implemented as classifiers. The robustness of the ANN diagnostic concept is also demonstrated by the addition of white noise to the “measured” signals. The implementation of the new concept is demonstrated by testing and diagnosis of a second order notch cell realized with one operational amplifier. Single soft and catastrophic faults are considered in detail and an example of the diagnosis of double soft faults is also given.