Analysis of Power Supply Noise in the Presence of Process Variations

Characterizing the impact of variability on circuit performance measurements (delay, power, and signal integrity) is necessary to avoid chip failure. The authors present a comprehensive methodology for analyzing the impact of device and metal variations on the power supply noise, and hence the signal integrity, of on-chip power grids.     

Pressure drop prediction in hydraulic transport of bi-dispersed particles of coal and copper ore in pipeline

Hydraulic transport studies with coal and copper ore have been carried out in a 0.0254 m and a 0.019 m diameter pipeline to observe the effect of solids concentration, surface characteristics and particle size distribution on pressure drop. The coarse coal showed a lower pressure drop than the fines at any velocity of suspension, whereas copper ore, exhibited the opposite trend. It has been observed, that the pressure drop for hydraulic transportation of bi-dispersed particles is a minimum at certain weight proportions of coarse to fines, as compared to that for the transportation of either of the single size. Based on the experimental results, an empirical expression was developed for the prediction of pressure gradient.     

An efficient file structure for document retrieval in the automatedoffice environment

A file system tailored to the general needs of the office environment is proposed. This system supports large numbers of a wide variety of documents and inexact fuzzy queries on the documents. The file system is based on a multilevel file structure that combines and extends multikey extendible hashing and signature files to create a document-retrieval system that is more time efficient than other previously proposed systems and is also space efficient     

Review on nano-and microfiller-based polyamide 6 hybrid composite: Effect on mechanical properties and morphology

Polyamide 6 (PA6)-based composites are of evolving interest due to its high strength, wear resistance, and barrier properties. The use of binary composites mostly with nanomaterial and glass fibers has been reviewed and presented in literature. However to obtain a balance of properties like stiffness, toughness, and strength along with cost reduction, ternary composites of PA6 have been designed. To achieve the balance, PA6 blend-based composites, with combination of microfiller/nanofiller or PA6 with combination micro-microfiller, PA6 with microfiller/nanofiller and fiber have been designed. The properties of PA6-based ternary hybrid composites depend on type of dispersed phase used, presence of compatibilizer, type of filler used (nanofiller or microfiller or fiber or hybrid) and combination of fillers used. However, a review in this direction is not available in literature. Here, in this study, an overall understanding of various fillers, dispersed phase, and their combinations can be understood along with the discussion on effect of these on tensile properties and morphology of hybrid composite. In this study, an attempt has been made to review the various fillers and dispersed phase and their combinations which have been used in designing the PA6 hybrid composite with good balance of stiffness, toughness, and strength.     

Highly selective homogeneous ethylene epoxidation in gas (ethylene)‐expanded liquid: Transport and kinetic studies

Recently a homogeneous liquid‐phase ethylene oxide (EO) process with nearly total EO selectivity, catalyzed by methyltrioxorhenium with H₂O₂ as an oxidant, was reported. Fundamental mass transfer and kinetic studies of this reaction are reported in the present work. Volumetric expansion studies revealed that the liquid reaction phase (methanol + H₂O₂/H₂O) is expanded by up to 12% by compressed ethylene in the 20–40^°C range and up to 50 bars. This represents an increase in ethylene solubility by approximately one‐order of magnitude, attributed to the unique exploitation of near‐critical ethylene (P_c = 50.76 bar; T_c = 9.5^°C). Interphase mass‐transfer coefficients for ethylene dissolution into the liquid phase were obtained experimentally. Operating at conditions that enhanced the ethylene solubility and eliminated interphase mass‐transfer limitations maximized the EO productivity (1.61–4.97 g EO/h/g cat), rendering it comparable to the conventional process. Intrinsic kinetic parameters, estimated from fixed‐time semibatch reactor studies, disclosed the moderate activation energy (57 ± 2 kJ/mol). © 2012 American Institute of Chemical Engineers AIChE J, 59: 180–187, 2013     

A strategy for designing inhibitors of beta-amyloid toxicity

beta-Amyloid peptide is the major protein component of Alzheimer's plaques. When aggregated into amyloid fibrils, the peptide is toxic to neuronal cells. Here, an approach to the design of inhibitors of beta-amyloid toxicity is described; in this strategy, a recognition element, which interacts specifically with beta-amyloid, is combined with a disrupting element, which alters beta-amyloid aggregation pathways. The synthesis, biophysical characterization, and biological activity of such an inhibitor is reported. This prototype inhibitor is composed of residues 15-25 of beta-amyloid peptide, designed to function as the recognition element, linked to an oligolysine disrupting element. The inhibitor does not alter the apparent secondary structure of beta-amyloid nor prevent its aggregation; rather, it causes changes in aggregation kinetics and higher order structural characteristics of the aggregate. Evidence for these effects includes changes in fibril morphology and a reduction in thioflavin T fluorescence. In addition to its influence on the physical properties of beta-amyloid aggregates, the inhibitor completely blocks beta-amyloid toxicity to PC-12 cells. Together, these data suggest that this general strategy for design of beta-amyloid toxicity inhibitors is effective. Significantly, these results demonstrate that complete disruption of amyloid fibril formation is not necessary for abrogation of toxicity.     

Lipopolysaccharide and IL-1 alpha activate CNS pathways as measured by NK cell activity

An outward current (Iout) was produced by stereoisomers of beta-hydroxy-L-glutamic acid (L-BHGA), an L-glutamic acid (L-Glu) derivative, applied by brief pneumatic pressure ejection on an identifiable neurone type, v-LCDN (ventral-left cerebral distinct neurone), of Achatina fulica Férussac. However, L- and D-Glu were almost ineffective on this neurone type. The pharmacological features of this Iout caused by L-BHGA were elucidated in the present study. According to the dose (pressure duration)-response studies on the L-BHGA stereoisomers that produced the Iout, the effective potency of threo-L-BHGA was approximately similar to that of erythro-L-BHGA. The dose (pressure duration)-response curve of quisqualic acid was shifted towards the left direction from those of threo-and erythro-L-BHGA, suggesting that the binding activity of quisqualic acid to the receptors would be stronger than those of the L-BHGA stereoisomers. GABA, glycine and L-homocysteic acid showed an inward current (Iin) on this neurone type, in contrast to the Iout caused by L-BHGA. beta-Alanine and taurine had absolutely no effect. Therefore, no amino acid inhibitory neurotransmitter candidate was found for this neurone type except for L-BHGA. It was assumed that L-BHGA, in either threo-or erythro-configuration, would be an inhibitory neurotransmitter for this neurone type. Mammalian L-Glu receptor antagonists. D(-)-AP-5, (+/-)-CPP, CNQX and L(+)-AP-3, applied by perfusion, showed no effect on the Iout of v-LCDN caused by threo-L-BHGA, indicating that the features of the inhibitory receptor activated by L-BHGA were much different from those of any type of the mammalian L-Glu receptors. Among the inhibitors of ATP-sensitive K+ channel, glipizide significantly inhibited the Iout caused by threo-L-BHGA, whereas tolbutamide did not. Inhibitors of intracellular signal transduction systems, H-7, H-8, H-9, staurosporine, calphostin C, KT5823 and W-7, had no effect on the Iout caused by threo-L-BHGA, suggesting that the receptors activated by threo-L-BHGA would be ionotropic.     

Modeling of compressible phase-change heat transfer in a Taylor-Bubble with application to pulsating heat pipe (PHP)

ABSTRACT

The present work deals with the development of a compressible phase-change solver and implementation toward the numerical modeling and investigation of a part-unit cell of a pulsating heat pipe (PHP). The fundamental understanding of the working of the part-unit cell is imperative in the development of a complete Computational Fluid Dynamics (CFD) model of a PHP. The compressible model developed in the present work is based on the Volume-of-Fluid solver of the open source CFD software, OpenFOAM, in which the contour-based interface reconstruction algorithm and the contact-line evaporation model have been incorporated. Owing to the lack of a single standard benchmark validation case for a compressible phase-change solver, a huge emphasis in the present work is laid on the solver development and validation, the latter part of which is conducted in stages. Furthermore, simulations for the formation of a Taylor-Bubble through a constrained bubble growth are performed and the fallacy of an incompressible solver is shown distinctly. The validated solver is used to model a part-unit cell of a PHP and a parametric study is performed on the part-unit cell. The effect of variation of evaporator length, evaporator superheat, and liquid fill ratio on the performance of the PHP is discussed.     

Afferent signals to the CNS appear not to condition the modulation of interleukin-1 receptors in the hippocampus

Conditioned alteration of natural killer (NK) cell activity was used as an indicator of the functional bidirectional communication between the immune and central nervous systems. Poly I:C and lipopolysaccharide (LPS) from Escherichia coli and Salmonella typhimurium were used as unconditioned stimuli and odor of camphor as the conditioned stimulus. An attempt was made to demonstrate the role of central interleukin (IL-1) receptors in this communication process. Brain IL-1 receptors were down-regulated by treatment with 50 microg/mouse of LPS from S. typhimurium, but not with the same dose of LPS from E. coli or poly I:C. A significant level of conditioned augmentation of NK cell activity was observed with poly I:C. Conditioned alteration in NK cell activity was also observed with LPS from E. coli, but at much lower level than poly I:C. NK cell activity was not conditioned with LPS from S. typhimurium at the same dose as E. coli LPS, but conditioned enhancement of NK cell activity was observed with a higher dose (100 microg) of S. typhimurium LPS. These results suggest that modulation of central IL-1 receptors do not seem to play a role in the conditioned augmentation of NK cell activity.     

Support vector regression with parameter tuning assisted by differential evolution technique: Study on pressure drop of slurry flow in pipeline

This paper describes a robust support vector regression (SVR) methodology that offers superior performance for important process engineering problems. The method incorporates hybrid support vector regression and differential evolution technique (SVR-DE) for efficient tuning of SVR meta parameters. The algorithm has been applied for prediction of pressure drop of solid liquid slurry flow. A comparison with selected correlations in the literature showed that the developed SVR correlation noticeably improved prediction of pressure drop over a wide range of operating conditions, physical properties, and pipe diameters.