A 300-GHz CMOS 7-by-7 Detector Array for Optics-less THz Imaging with Scan-less Target Object

Journal of Infrared, Millimeter, and Terahertz Waves - In this work, a 300-GHz 7?×?7 detector array based on a 65-nm Si CMOS technology has been developed and transmission imaging...     

A numerical study of a methane-fueled gas engine generator with addition of hydrogen using cycle simulation and DOE method

Conventional fossil fuels for combustion systems, such as gasoline and diesel, have a number of problems related to energy security and emissions. Alternative fuels, such as methane, hydrogen, and mixtures of these two gases, are being promoted as clean energy substitutes for primary fossil fuels. Natural gas (which consists mainly of methane) is one of the most promising of these fuels, providing lower cost, cleaner emissions and is direct applicable to existing combustion systems. However, the use of natural gas as fuel can adversely affect engine performance. Therefore, hydrogen is sometimes used as an additive, as its higher burning rate often leads to enhanced combustion. In this study, cycle simulation was used to numerically investigate the performance and emission characteristics of an engine employed primarily to power a generator, and fueled with methane and methane - hydrogen blends. Dominant parameters such as excess air ratio, spark timing, and volume percent of hydrogen content, were investigated as independent variables. The fundamental effect of hydrogen on methane combustion was investigated for a fixed excess air ratio of 1.2 and a spark timing of 14CA(Crank Angle) BTDC (Before Top Dead Center), with an accompanying reduction in ignition delay. By varying the excess air ratio, hydrogen was demonstrated to play an important role in extending the lean operating limit. The DOE (Design of Experiment) method was applied to study MBT (Maximum Brake Torque) spark timing for various excess air ratios and hydrogen contents. When MBT spark timing was employed, maximum brake torque could be achieved under leaner burning conditions by increasing the hydrogen content.     

Decontamination of uranium-contaminated waste oil using supercritical fluid and nitric acid

The waste oil used in nuclear fuel processing is contaminated with uranium because of its contact with materials or environments containing uranium. Under current law, waste oil that has been contaminated with uranium is very difficult to dispose of at a radioactive waste disposal site. To dispose of the uranium-contaminated waste oil, the uranium was separated from the contaminated waste oil. Supercritical R-22 is an excellent solvent for extracting clean oil from uranium-contaminated waste oil. The critical temperature of R-22 is 96.15 °C and the critical pressure is 49.9 bar. In this study, a process to remove uranium from the uranium-contaminated waste oil using supercritical R-22 was developed. The waste oil has a small amount of additives containing N, S or P, such as amines, dithiocarbamates and dialkyldithiophosphates. It seems that these organic additives form uranium-combined compounds. For this reason, dissolution of uranium from the uranium-combined compounds using nitric acid was needed. The efficiency of the removal of uranium from the uranium-contaminated waste oil using supercritical R-22 extraction and nitric acid treatment was determined.     

Upper layer enhancements for fast call setup in cdma2000 revision D

Fast call setup (FCS) technology, a recent enhancement in revision D of cdma2000/sup /spl reg// in 3rd generation partnership project 2 (3GPP2), is a set of mechanisms for reducing call setup latency. FCS technology comprises MS tracking mechanisms, channel assignment procedures, paging mechanisms, and traffic channel initialization procedures. The combination of these techniques contributes to the improvement of the overall call setup delay. This article discusses the functional aspects of these enhancements, and their quantitative and qualitative performance.     

Divide et impera: Acceleration of DTI tractography using multi‐GPU parallel processing

Diffusion tensor imaging (DTI) tractography technique represents neural fiber pathways by using local tensor information based on water diffusion anisotropy in brain white matter. However, DTI tractography is often unable to reconstruct crossing, kissing, and branching fiber trajectories due to intrinsic limitations of DTI. Increasingly complex tractography algorithms provided reliable and visually pleasing results, yet at an increasing computational cost in comparison with simple tractography algorithms. To shorten the computation time, we developed multi‐GPU (graphics processing unit)‐based parallelized versions of deterministic and probabilistic tractography algorithms to investigate their utility for near‐real time tractography. We were able to dramatically reduce the computation time using multiple GPUs (three NVIDIA TESLA C1060s) in comparison to the central processing unit (CPU) sequential processing. Deterministic tractography could accelerate 101 times faster, and probabilistic tractography could accelerate 63 times faster. The results showed that parallel tractography algorithm is well suited with GPU which has fundamentally parallelized architecture. © 2013 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 23, 256–264, 2013     

Experimental study on fundamental effect of H2 for catalytic soot oxidation with Pt/CeO2 using a flow reactor system

The effect of hydrogen on catalytic soot oxidation was investigated to find new conditions for lowering the regeneration temperature in catalyzed diesel particulate filtration with hydrogen. Soot oxidation experiments using a flow reactor with a Pt/CeO₂ catalyst were carried out to represent catalyzed diesel particulate filtration. Under conditions using more than 6% hydrogen with water, the soot oxidation by hydrogen started at 155 °C for loose contact conditions and at 175 °C for tight contact conditions. The soot oxidation rate tended to increase with increasing concentrations of hydrogen and oxygen. In contrast, no difference was observed with various water concentrations. The HO₂ generated during hydrogen oxidation oxidized soot at low temperature. The soot oxidation temperature of 155 °C was lower than the regeneration temperature in catalyzed diesel particulate filtration reported previously.     

Mechanism Design of a Robotic Leg for Running Considering Radial Force Producibility and Tangential Mobility

International Journal of Control, Automation and Systems - A robotic leg of high-speed locomotion should be designed such that the mobility and the force producibility are maximized simultaneously....