Analog CMOS circuit design and characterization for optical coherence tomography signal processing

We have developed a custom analog CMOS circuit to perform the signal processing for an optical coherence tomography imaging system. The circuit is realized in a 1.5 /spl mu/m low-noise analog CMOS technology. The circuitry extracts the Doppler frequency from the signal and electrically mixes this with the original signal to provide a filtered A-scan. The circuitry was used to produce a two-dimensional image of an onion.     

Generating human-like soccer primitives from human data

Recently, interest in analysis and generation of human and human-like motion has increased in various areas. In robotics, in order to operate a humanoid robot, it is necessary to generate motions that have strictly dynamic consistency. Furthermore, human-like motion for robots will bring advantages such as energy optimization.This paper presents a mechanism to generate two human-like motions, walking and kicking, for a biped robot using a simple model based on observation and analysis of human motion. Our ultimate goal is to establish a design principle of a controller in order to achieve natural human-like motions. The approach presented here rests on the principle that in most biological motor learning scenarios some form of optimization with respect to a physical criterion is taking place. In a similar way, the equations of motion for the humanoid robot systems are formulated in such a way that the resulting optimization problems can be solved reliably and efficiently.The simulation results show that faster and more accurate searching can be achieved to generate an efficient human-like gait. Comparison is made with methods that do not include observation of human gait. The gait has been successfully used to control Robo-Erectus, a soccer-playing humanoid robot, which is one of the foremost leading soccer-playing humanoid robots in the RoboCup Humanoid League.     

Synthesis of Amido‐N‐imidazolium Salts and their Applications as Ligands in Suzuki–Miyaura Reactions: Coupling of Hetero‐ aromatic Halides and the Synthesis of Milrinone and Irbesartan

A new catalytic system based on palladium‐amido‐N‐heterocyclic carbenes for Suzuki–Miyaura coupling reactions of heteroaryl bromides is described. A variety of sterically bulky, amido‐N‐imidazolium salts were synthesized in high yields from the corresponding anilines. This catalytic system effectively promoted Suzuki–Miyaura couplings of heteroaryl bromides and chlorides with a range of boronic acids to give the corresponding aryl compounds in high yield. The yield was increased with increasing steric bulkiness of the substituted group. Especially, 1‐(2,6‐diisopropylphenyl)‐3‐N‐(2,4,6‐tri‐tert‐butylphenylacetamido)imidazolium bromide ( 4bc ) exhibited 850,000 TON in the coupling reaction of 2‐bromopyridine and phenylboronic acid. In addition, pharmaceutical compounds such as milrinone and irbesartan were synthesized via Suzuki–Miyaura coupling using sterically bulky, amido‐N‐imidazolium salt ( 4bc ) as a ligand.     

One-step synthesis of composite electrolytes of Eu-doped ceria and alkali metal carbonates

Europium-doped ceria (EDC, Ce_0.9Eu_0.1O_2−δ)/alkaline carbonate (LNC, (Li,Na)₂CO₃) composite ceramics prepared through a one-step citrate-based route were analyzed by powder X-ray diffraction, infrared and laser Raman spectroscopies as well as scanning and transmission electron microscopy. The electrochemical behavior of the electrolyte material was studied by impedance spectroscopy in air, CO₂ and N₂ + H₂ (90/10 vol%, respectively) gas mixtures, in the temperature range 300–600 °C. The sub micrometric and even nanosized ceramic particles appeared as merged inside the mixed carbonates, with modest grain to grain necking. The EDC/LNC composite electrolytes showed a conductivity of 0.27 S cm⁻¹ at 600 °C in air, amongst the best ever reported, exceeding the usual requirements for fuel cell applications.     

High piezoelectric actuation response in graded Nd2O3 and ZrO2 doped BaTiO3 structures

High electromechanical strains have been developed in this study in Barium Titanate ceramics, suitably doped with Nd and Zr to form a controlled concentration gradient, leading to a dome-like structure on sintering. Compacted pellets constituted of layers of barium titanate powder of varying minor amounts of Nd and Zr powders, incorporated as nitrates precursors, acquire this dome shape on sintering at 1300?C1320^oC and cooling to the ambient temperature, the result of the residual thermoelastic strain. The dome structures exhibit high electromechanical responses, and the piezoelectric coefficients (deduced from electric field induced strains measurements in dome-up and dome-down positions) are also found to be exceptionally high. These Nd and Zr doped barium titanate structures could find applications as an environmentally benign material for fabrication of high displacement functionally graded electromechanical actuators in a single sintering step process.     

Adaptive relay co-ordination using a busbar splitting approach for a system integrity protection scheme

Power system faults can often result in excessively high currents. If sustained for a long time, such high currents can damage system equipment. Thus, it is desirable to operate the relays in the minimum possible time. In this paper, a busbar splitting approach is used for adaptive relay setting and co-ordination purposes for a system integrity protection scheme (SIPS). Whenever a fault occurs, the busbar splitting scheme splits a bus to convert a loop into a radial structure. The splitting schemes are chosen such that the net fault current is also reduced. Busbar splitting eliminates the dependency upon minimum breakpoints set (MBPS) and reduces the relay operating time, thus making it adaptive. The proposed methodology is incorporated into the IEEE 14-bus and IEEE 30-bus systems with single and multiple fault conditions. The modeling and simulation carried out in ETAP, and the results of the proposed busbar splitting-based relay co-ordination are compared with the MBPS splitting-based relay co-ordination.     

A simple decision tree-based disturbance monitoring system for VSC-based HVDC transmission link integrating a DFIG wind farm

Fault detection and classification is a key challenge for the protection of High Voltage DC (HVDC) transmission lines. In this paper, the Teager–Kaiser Energy Operator (TKEO) algorithm associated with a decision tree-based fault classi f ier is proposed to detect and classify various DC faults. The Change Identification Filter is applied to the average and differential current components, to detect the first instant of fault occurrence (above threshold) and register a Change Identified Point (CIP). Further, if a CIP is registered for a positive or negative line, only three samples of currents (i.e., CIP and each side of CIP) are sent to the proposed TKEO algorithm, which produces their respective 8 indices through which the, fault can be detected along with its classification. The new approach enables quicker detection allowing utility grids to be restored as soon as possible. This novel approach also reduces computing complexity and the time required to identify faults with classification. The importance and accuracy of the proposed scheme are also thor oughly tested and compared with other methods for various faults on HVDC transmission lines.     

Study of heat and mass transfer in indoor conditions for distillation

An indoor simulation study was carried out to evaluate heat and mass transfer relation for a semi-cylindrical metallic (opaque) condensing cover for higher yields at different operating temperatures under free and forced modes of operation. The objective is to design a distillation unit for higher yield for commercialization, particularly in India. Experiments have been conducted for the operating temperature range of 40°C to 80°C in a steady-state condition by using constant temperature bath. Data (temperature and yield) obtained from experimentation have been used to determine the values of coefficient C and n and, consequently, convective as well as evaporative heat transfer coefficients. It is inferred that a higher yield is obtained with an increase of temperature in the forced mode of operation as compared to that in the natural mode of operation due to a fast release of heat from the condensing cover.     

Effects of fiber surface grafting by functionalized carbon nanotubes on the interfacial durability during cryogenic testing and conditioning of CFRP composites

Carbon fiber reinforced epoxy (CE) composite is ideal for a cryogenic fuel storage tank in space applications due to its unmatched specific strength and modulus. In this article, inter-laminar shear strength (ILSS) of carbon fiber/epoxy (CE) composite is shown to be considerably improved by engineering the interface with carboxyl functionalized multi-walled carbon nanotube (FCNT) using electrophoretic deposition technique. FCNT deposited fibers from different bath concentrations (0.3, 0.5, and 1.0 g/L) were used to fabricate the laminates, which were then tested at room (30°C) and in-situ liquid nitrogen (LN) (−196°C) temperature as well as conditioning for different time durations (0.25, 0.5, 1, 6, and 12 h) followed by immediate RT testing to study the applicability of these engineered materials at the cryogenic environment. A maximum increment in ILSS was noticed at bath concentration of 0.5 g/L, which was ~21% and ~ 17% higher than neat composite at 30°C and − 196°C, respectively. Short-term LN conditioning was found to be detrimental due to developed cryogenic shock, which was further found to be compensated by cryogenic interfacial clamping upon long-term exposure.     

Fullerene polymer film as a highly efficient photocatalyst for selective solar fuel production from CO2

C₆₀-based polymeric systems have been constantly anticipated for sustainable solar energy conversion. Reported, herein is a C₆₀ polymer film as visible light active photocatalyst for efficient and selective reduction of CO₂ for the first time. The C₆₀ polymer photocatalyst is synthesized via covalent coupling of C₆₀ monomer units consisting of tetra substituted C₆₀-pyrene conjugates through spacer groups. The synthesized C₆₀ polymer photocatalyst possesses an extended network of well-defined repeating monomer units with good stability and visible light-induced photocatalytic activity. The enhanced visible light harvesting ability of C₆₀ polymer photocatalyst reasonably yields it with higher catalytic ability than its monomer unit. The C₆₀ polymer film photocatalyst upon coupling with the biocatalyst carries out highly selective visible light driven reduction of CO₂ to HCOOH (239.46 μmol). The tandem way of incorporating C₆₀ into visible light active polymeric films for continuous use may be highly rewarding for their extended photocatalytic activity for solar fuel production from CO₂. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48536.