A functional hybrid memristor crossbar-array/CMOS system for data storage and neuromorphic applications

Crossbar arrays based on two-terminal resistive switches have been proposed as a leading candidate for future memory and logic applications. Here we demonstrate a high-density, fully operational hybrid crossbar/CMOS system composed of a transistor- and diode-less memristor crossbar array vertically integrated on top of a CMOS chip by taking advantage of the intrinsic nonlinear characteristics of the memristor element. The hybrid crossbar/CMOS system can reliably store complex binary and multilevel 1600 pixel bitmap images using a new programming scheme.     

Pressure effects on Coriolis mass flowmeters

The current status of available work regarding the pressure effect on Coriolis mass flowmeters is reviewed, which shows significant improvement in the latest generation of Coriolis flowmeters. A theoretical method using the linear damping model is proposed to understand the pressure effect. This new method applied to Coriolis flow sensors provides intuitive insight into the flow-generated signal by studying undamped natural frequencies and mode shapes. Most importantly this method can be used to model virtually any shape and configuration of flow sensors as found in the practical design. It is found that when the pressure changes it alters the superimposed contribution and the mass flow measurement can deviate from the reference condition. Experimental results from both low and high pressure flow tests are reported, which are in general agreement with the theoretical prediction. Further specific work is finally suggested which may advance our understanding and improve the Coriolis mass flow measurement technology.     

Composition and nutritive value of cormels of Colocasia esculenta (L.) Schott

The nutritional quality of the cormels of Colocasia esculenta (L.) Schott cultivar ‘Guavir’ was determined chemically and biologically in feeding experiments with weanling rats. The contents of starch and unavailable carbohydrates (cellulose, hemicellulose and pectin) were 54 and 15% of the dry matter respectively. Lipid accounted for less than 1% of the dry matter. Palmitic, oleic and linoleic acids were the main fatty acids in the lipids, with linoleic acid predominating. The content and fatty acid composition of the individual lipids was examined. Crude protein amounted to 10.4% of the dry matter. This protein was low in the sulphurcontaining amino acids and tryptophan, but contained adequate levels of the other essential amino acids. Diets containing raw cormel meal gave severely depressed net protein utilisation (NPU) and total nitrogen and carbohydrate digestibility when fed ad libitum to weanling rats. Both NPU and nitrogen and carbohydrate digestibility improved when the cormel meal was cooked prior to inclusion in the diets but such diets still did not support growth in weanling rats.     

Modeling and analysis of multiservice queuing system for WiMAX network

An analytical queuing model is proposed for the classified services of WiMAX network. Simulation model is also developed that corresponds to the Markovian analytical model using Java modeling tool (JMT) . This is a new and efficient discrete event tool for queuing network modeling and workload analysis. QoS metrics have been evaluated for the multi-rate traffic in multiple scenarios. Results obtained from simulation are compared for validation and analysis. Outcomes show that the proposed model is more efficient than the conventional method by improving residence time,response time,increasing system throughput and efficiency at queuing level with a slight degradation in call acceptance factor.     

Enhanced thermoelectric properties in Ge-doped and single-filled skutterudites prepared by unique melt-spinning method

In this paper, we determined an effective substitution of Ge at Sb sites in Nd-filled p-type skutterudites, a series of Nd_.9Fe₂Co₂Sb_12-xGe_x compounds with compositions of x?=?0, 0.1, 0.2, 0.3 and 0.4 were synthesized by home-made induction melting, assembled inside the glove box and followed by spark plasma sintering process (SPS). The thermoelectric properties are investigated as a function of Ge doping content with fixed Nd-filler at 0.9 and the formation of skutterudite phase is characterized by X-ray diffraction. All samples possess positive Seebeck coefficients, representing effective p-type doping. It is observed that the electrical conductivity decreases with decreasing Ge doping concentrations while increased with temperature due to bipolar effect. The lightly doped samples (x?=?0.1 and 0.2) have lower lattice thermal conductivity over the entire temperature range, in which x?=?0.2 sample shows the highest ZT value of 0.82 at 700?K, which is 30% higher than that of the Ge-free sample. The improvement in ZT can be attributed to the optimized carrier concentration and reduced thermal conductivity. The enhancement of ZT through Ge doping, coupled with drastically reduced processing time, shows that these compounds may have great potential in application as p-type segments of the thermoelectric devices.     

Graphenothermal reduction synthesis of MnO/RGO composite with excellent anodic behaviour in lithium ion batteries

Mn(II) oxide/graphene oxide (MnO/RGO) composites were synthesized by an easy and cost-effective graphenothermal reduction method. The surface morphology, structure, chemical composition and electrochemical behaviour of the resulting composites were investigated in detail. The MnO/RGO composite exhibited a high surface area (115.7 m²/g), which led to the high discharge capacity, enhanced cycling stability, and outstanding rate capability as anode in Li-ion batteries (LIBs). The MnO/RGO composite exhibited an higher initial discharge capacity of 1607 mA h/g at a current density of 100 mA/g and maintained 94% of its reversible capacity over 100 consecutive cycles. Furthermore, MnO/RGO composite could preserve a significantly higher capacity of 847 mA h/g for 150 cycles even at a high current density of 250 mA/g. The excellent electrochemical properties result from the existence of highly conductive RGO and a short transportation span for both Li-ions and electrons. The developed MnO/RGO composite materials hold highly promising prospects in LIBs.     

Modeling of aggregation kernel using Monte Carlo simulations of spray fluidized bed agglomeration

The present work attempts to consider the microscopic mechanisms of spray fluidized bed agglomeration while modeling the macroscopic kinetics of the process. A microscale approach, constant volume Monte‐Carlo simulation, is used to analyze the effects of micro‐processes on the aggregation behavior and identify the influencing parameters. The identified variables, namely the number of wet particles, the total number of particles, and the number of droplets are modeled and combined in the form of an aggregation kernel. The proposed kernel is then used in a one‐dimensional population balance equation for predicting the particle number density distribution. The only fitting parameters remaining in the population balance system are the collision frequency per particle and a success fraction accounting for the dissipation of kinetic energy. Predictions of the population balance model are compared with the results of Monte‐Carlo simulations for a variation of significant operating parameters and found to be in good agreement. © 2014 American Institute of Chemical Engineers AIChE J, 60: 855–868, 2014     

Degradation of waste High-density polyethylene into fuel oil using basic catalyst

High-density polyethylene (HDPE) has been degraded thermally and catalytically using MgCO₃ at 450 °C into liquid fraction in a batch reactor. Different conditions like temperature, time and catalyst ratio were optimized for the maximum conversion of HDPE into liquid fraction. Catalytic degradation yielded 92% liquid fraction whereas 90% wax was obtained with thermal degradation. The composition of the liquid fraction was characterized by physicochemical properties of petroleum fuel tests. The catalytic liquid fraction consisted of high concentration of C₈-C₉, C₁₃-C₁₄ and C₁₇-C₁₈ hydrocarbons. The distillation data showed that ∼50% of the fraction has boiling point in the range of gasoline and ∼50% in the range of diesel oil.     

Using NMR displacement measurements to probe CO2 entrapment in porous media

Carbon dioxide sequestration in aquifers is seen as a potential climate change mitigation technique. One physical mechanism by which this could occur is capillary trapping of discrete pore‐scale CO₂ bubbles (referred to as ganglia) in the pore space. Nuclear magnetic resonance (NMR) techniques were used to quantify the spatial distribution and pore environment of such CO₂ entrapment in a model porous medium (random glass bead packing). 3D images revealed a relatively macroscopically homogeneous CO₂ entrapment, even though the image resolution is insufficient to resolve individual CO₂ ganglia. Quantification of the pore environment of the CO₂ ganglia was achieved using NMR displacement propagators (displacement probability distributions), acquired both before and after CO₂ entrapment. Lattice Boltzmann (LB) simulations were used to facilitate interpretation of the propagator statistics by considering various pore environments in which CO₂ could become trapped. Comparison with the experimental data suggests that CO₂ is preferentially entrapped in comparatively larger pores. © 2010 American Institute of Chemical Engineers AIChE J, 2011