BIST/Digital-Compatible Testing of RF Devices Using Distortion Model Fitting

Testing of Radio Frequency (RF) circuits for nonlinearity specifications generally requires the use of multiple test measurements thereby contributing to increased test cost. Prior RF test methods have suffered from significant test calibration effort (training for supervised learners) when using compact tests or from increased test time due to direct specification measurement. On the other hand, due to aggressive technology scaling, there are plenty of digital transistors available that can be used to simplify testing of Analog/Mixed-Signal (AMS) and RF devices. In this paper, an RF test methodology is developed that: (a) allows RF devices to be tested for several distortion specifications using distortion model fitting algorithms in test time comparable to what can be achieved using supervised learning techniques while retaining the accuracy of direct specification measurement, (b) allows multiple RF specifications to be determined concurrently from a single data acquisition and (c) allows digital-compatible testing/BIST to be performed using digital testers or on-chip built in self-test (BIST) circuitry. With regard to (a), a key benefit is that no training of supervised learning algorithm is necessary. The proposed method based on distortion model fitting is shown to give excellent results across common RF performance metrics while providing ~10× improvements in test time compared to previous methods.     

Template-free synthesis of flower-shaped zero-valent iron nanoparticle: Role of hydroxyl group in controlling morphology and nitrate reduction

Well-dispersed single phasic flower-like zero valent iron nanoparticles have been synthesized under aerobic conditions using a facile approach without the addition of any additives or templates. The role of hydroxyl groups of polyhydroxy alcohols in controlling surface morphology of nanoparticles has been thoroughly investigated. The obtained nanoparticles have been characterized by TEM, FE-SEM, XRD and BET surface area analyzer. Electron microscopy analyses reveal that the solvent plays a pivotal role in determining the morphology of the particles. With increase in viscosity of the solvent, formations of ‘petal-like’ structures, which are joined at the center are formed. The nitrate removal efficiency of the iron nanoparticles synthesized in different solvents has been studied and it is seen that the “flower-like” iron nanoparticles were most active in the removal of nitrate. Experiments have been done by varying (i) nitrate concentrations, (ii) nanoparticle dose, and (iii) type of nanoparticles. The results conclude that highest removal efficiency (～100%) was achieved when the nanoparticle dose was 2.88 g/L, even for high nitrate concentrations up to 400 mg/L. The major highlight of this work is the fact that even though the nanoparticles synthesized in glycerol-water mixture have larger size in comparison to the other nanoparticles, still they remove the nitrates with highest efficiency.”     

Investigation of Eccentric Open Eye Formation in a Slab Caster Tundish

Metallurgical and Materials Transactions B - Inert gas shrouding in tundish can result in the formation of a tundish open eye (TOE) due to the presence of reversed flows on the upper surface of the...     

Intermetallic Precipitation in Low-Density Steel

Metallurgical and Materials Transactions A - Low-density steels (LDS) represent a relatively new class of material that contains a large concentration of aluminum. In the present work, we studied...     

Analytic solution for planar indeterminate impact problems using an energy constraint

This work proposes an analytic method for resolving planar multi-point indeterminate impact problems for rigid-body systems. An event-based approach is used to detect impact events, and constraints consistent with the rigid-body assumption are used to resolve the indeterminacy associated with multi-point impact analysis. The work-energy relation is utilized to determine post-impact velocities based on an energetic coefficient of restitution to model energy dissipation, thereby yielding an energetically consistent set of post-impact velocities based on Stronge’s energetic coefficient of restitution for the treatment of rigid impacts. The effect of stick–slip transition is analyzed based on Coulomb friction. This paper also discusses the transition from impact to contact. This analysis is essential for considering the rocking block problem that is used as an example herein. The predictions of the model for the rocking block problem are compared to experimental results published in the literature. An example of a planar ball undergoing two-point impact is also presented.     

Smart-MEMS based inertial measurement units: gyro-free approach to improve the grade

Microsystem Technologies - Inertial measurement units (IMU) are essentially a combination of acceleration and rotation rate sensors, generating position and attitude information. For tactical and...     

Thermoelectric cold-chain chests for storing/transporting vaccines in remote regions

The cold chain is one of the key elements of the preventive health-care delivery system. Vaccines have to be carried long distances, stored in remote places and during this period the temperature has to be maintained within certain specified values. Realizing the needs of such requirements, the Department of Science & Technology, New Delhi (Govt. of India) assigned a project to the R&D Division of MECON, Ranchi for development of Thermoelectric Cold-Chain Chest operated by 12 V DC vehicular battery. The resulting portable thermoelectric (i.e. Peltier effect) Cold-Chain Chest (TCC) operated successfully even in an ambient environment of 45 °C, mainly for preserving and transporting life-saving medicines for urban as well as rural areas.     

Characterization of Cu-SiO2 Composite Synthesized by Hydrogen Reduction of Chalcopyrite Concentrate Followed by Acid Leaching

A Ghatshila chalcopyrite concentrate (average particle size, 50 μm) containing primarily CuFeS₂ and SiO₂ (Cu 16 pct, Fe 26 pct, S 14 pct, Si 5 pct, and O 33 pct) was reduced by a stream of hydrogen in a horizontal tube furnace at 1323 K (1050 °C), producing a mixture of Cu (26 pct), SiO₂, Fe₂O₃, Fe₃O₄, Cu₂O, and Fe. Subsequent acid leaching with 1 M HCl solution of the reduction product removed all iron oxides and iron, and other impurities too, leaving a Cu (53.3 pct) + SiO₂ mixture, with a small percentage of Cu₂O in it. This result compares well with the predicted final mixture of Cu (59 pct)-SiO₂ based on a mass balance on the starting concentrate. Elemental chemical analyses were done by energy-dispersive X-ray spectroscopy, which were crosschecked by atomic absorption spectroscopy in the majority of cases. The phase identification and microstructural characterization of Cu-SiO₂ mixtures were done by X-ray diffraction, Fourier transform infrared spectroscopy, Rietveld analysis, scanning electron microscopy, and high-resolution transmission electron microscopy (HRTEM). It was found that Cu-SiO₂ composites were formed in the final product, with a copper grain size of 385 nm.     

Lossy magnetic energy storage units for improvement in automatic generation control

Fast-acting energy storage devices can effectively damp electromechanical oscillations in a power system, because they provide storage capacity in addition to kinetic energy of the generator rotor, which can share the sudden changes in power requirement. Earlier studies showed the effectiveness of superconducting magnetic energy storage (SMES) for this purpose. The present paper analyses the characteristics of lossy magnetic energy storage (LMES) and shows the effectiveness of small-sized LMES units in improving power system transient response. Computer studies show that the optimal parameter settings of the power system are changed with the addition of an energy storage element.