Disorder in cellulosic fibers

Ruland's concept of an isotropic disorder function is applied to estimate the disorder parameter and the degree of crystallinity in a few cellulosic fibers: two cottons, native ramie, and a high-tenacity rayon. The results indicate an increase in disorder without any change in crystallinity on mercerization of native celluloses. On hydrolysis, with or without a pretreatment of mercerization, the samples exhibit a higher crystallinity, disorder remaining the same as for native celluloses. A ball-milled sample of “amorphous” cellulose is still found to be fairly crystalline with the lowest disorder. On being wetted in water and oven-dried, a distorted form of cellulose II with higher crystallinity and disorder was obtained. The polynosic fiber, Tufcel, has low values for the degree of crystallinity, disorder parameter, as well as crystallite dimension. A strong dependence of the degree of crystallinity on the crystallite size, particularly the lateral, is observed.     

Quadtree-based eigendecomposition for pose estimation in the presence of occlusion and background clutter

Eigendecomposition-based techniques are popular for a number of computer vision problems, e.g., object and pose estimation, because they are purely appearance based and they require few on-line computations. Unfortunately, they also typically require an unobstructed view of the object whose pose is being detected. The presence of occlusion and background clutter precludes the use of the normalizations that are typically applied and significantly alters the appearance of the object under detection. This work presents an algorithm that is based on applying eigendecomposition to a quadtree representation of the image dataset used to describe the appearance of an object. This allows decisions concerning the pose of an object to be based on only those portions of the image in which the algorithm has determined that the object is not occluded. The accuracy and computational efficiency of the proposed approach is evaluated on 16 different objects with up to 50% of the object being occluded and on images of ships in a dockyard.

Track following servo control for rotary piezoelectric motor based primary actuation in hard disk drives

In this paper, we show the tracking performance of a rotary piezoelectric motor based hard disk drive actuator. The actuator is built and modeled for positioning servo in disk drive systems. The Piezo motor replaces the voice-coil-motor based primary actuation. Simulation and experimental results for its servo system proves that it can help to achieve track density of more than 1000?KTPI.     

Synthesis of 3D nanostructured metal alloy of immiscible materials induced by megahertz-repetition femtosecond laser pulses

In this work, we have proposed a concept for the generation of three-dimensional (3D) nanostructured metal alloys of immiscible materials induced by megahertz-frequency ultrafast laser pulses. A mixture of two microparticle materials (aluminum and nickel oxide) and nickel oxide microparticles coated onto an aluminum foil have been used in this study. After laser irradiation, three different types of nanostructure composites have been observed: aluminum embedded in nickel nuclei, agglomerated chain of aluminum and nickel nanoparticles, and finally, aluminum nanoparticles grown on nickel microparticles. In comparison with current nanofabrication methods which are used only for one-dimensional nanofabrication, this technique enables us to fabricate 3D nanostructured metal alloys of two or more nanoparticle materials with varied composite concentrations under various predetermined conditions. This technique can lead to promising solutions for the fabrication of 3D nanostructured metal alloys in applications such as fuel-cell energy generation and development of custom-designed, functionally graded biomaterials and biocomposites.     

Effect of nano additives (titanium and zirconium oxides) and diethyl ether on biodiesel-ethanol fuelled CI engine

The present work is dedicated to the comparative experimental study of biodiesel-ethanol blends in a compression ignition engine using TiO₂ (Titanium oxide) nanoparticle, ZrO₂ (Zirconium oxide) nanoparticle and DEE (Diethyl ether) additives. The test fuels used are a blend of biodiesel (80%) -ethanol (20%) (denoted as BE), a blend of BE with 25 ppm Titanium oxide nanoparticle (denoted as BE-Ti), a blend of BE with 25 ppm Zirconium oxide nanoparticle (denoted as BE-Zr) and a blend of BE with 50 ml Diethyl ether (denoted as BE-DEE). Addition of nanoparticles increases the oxidation rate, reduces the light-off temperature and creates large contact surface area with the base fuel thereby enhancing the combustion with minimal emissions. Experimental results shown that addition of Titanium nanoparticles increased NOx, HC and smoke with lowered BSFC and CO. Whereas addition of Zirconium nanoparticles increases BSFC and HC emissions with lowered CO, CO₂ and smoke emissions in comparison with BE blends. DEE addition to BE blends improved the heat release rate and increased HC, CO emissions were observed with lowered BSFC, NOx and smoke. Simultaneous reduction of NOx and smoke indicates the effect of DEE on Low temperature combustion (LTC).

     

Antifungal activity of solventlessly synthesized organomercurials

A series of new barbituryl/thiobarbituryl substituted organomercurial derivatives 3a-i have been synthesised from pyrimidine derivatives 1a-c and arylmercuric chloride 2a-c over K(2)CO(3) under microwave irradiations (MWI). This solventless synthesis apart from eliminating organic solvent from workup step, also gave improved yield as compared to the conventional heating, with reaction time reduced from hours to minutes. The prepared compounds were tested against A. niger and A. flavous for their antifungal activity and were found to posses good activity.     

High-frequency modeling for cable and induction motor overvoltage studies in long cable drives

High-frequency simulation models for power cables and motors are key tools to aid a better understanding of the overvoltage problem in pulsewidth modulation drives with long feeders. In this paper, frequency responses of the cable characteristic and the motor input impedances are obtained experimentally and suitable models are developed to match the experimental results. Several lumped segments incorporating a lossy representation of the line are used to model the cable. The cable and induction motor models may be implemented using a computational tool such as MATLAB, thereby providing a convenient method to analyze the overvoltage phenomena. Simulation and experimental results are presented for a typical 3-hp induction motor, showing the suitability of the developed simulation models. The most promising dv/dt filter networks are also investigated through simulation analysis, and a design approach based on a tradeoff between filter losses and motor peak voltage is proposed. Experimental results of an RC filter placed at the motor terminals demonstrate the validity of the simulation models.     

Relative quantities of catalytically active CYP 2C9 and 2C19 in human liver microsomes: application of the relative activity factor approach

The relative catalytic activities of CYP2C9 and CYP2C19 in human liver microsomes has been determined using the approach of relative activity factors (RAFs). Tolbutamide methylhydroxylation and S-mephenytoin 4'-hydroxylation were used as measures of CYP2C9 and CYP2C19 activity, respectively. The kinetics of these reactions were studied in human liver microsomes, in microsomes from human lymphoblastoid cells, and in insect cells expressing CYP2C9 and CYP2C19. RAFs were calculated as the ratio of Vmax (reaction velocity at saturating substrate concentrations) in human liver microsomes of the isoform-specific index reaction divided by the Vmax of the reaction catalyzed by the cDNA expressed isoform. RAFs were also determined for SUPERMIX, a commercially available mixture of cDNA expressed human drug metabolizing CYPs formulated to achieve a balance of enzyme activities similar to that found in human liver microsomes. Lymphoblast RAF2C9 in human liver microsomes ranged from 54 to 145 pmol CYP/mg protein (mean value: 87), while a value of 251 pmol CYP/mg protein was obtained for SUPERMIX. Insect cell RAF2C9 in human liver microsomes ranged from 1.6 to 143 pmol CYP/mg protein (mean value: 49), while a value of 201 pmol CYP/mg protein was obtained for SUPERMIX. Both lymphoblast and insect cell RAF2C19 in human liver microsomes ranged from 4 to 45 pmol CYP/mg protein (mean values: 29 and 28, respectively), while a value of 29 pmol CYP/mg protein was obtained for SUPERMIX. The nature of the cDNA expression system used had no effect on the kinetic parameters of CYP2C9 as a tolbutamide methylhydroxylase, or of CYP2C19 as a S-mephenytoin hydroxylase. However insect cell expressed CYP2C19 (which includes oxidoreductase) had substantially greater activity as a tolbutamide methylhydroxylase when compared to lymphoblast expressed CYP2C19. The ratio of mean lymphoblast-determined RAF2C9 to RAF2C19 in human livers was 3.0 (range 1.6-17.9; n = 10), while this ratio for SUPERMIX was 8.6. The ratio of mean insect cell-determined RAF2C9 to RAF2C19 in human livers was 1.7 (range 0.04-16.2; n = 10), while this ratio for SUPERMIX was 7.0. Neither ratio is in agreement with the 20:1 ratio of immunoquantified levels of CYP2C9 and 2C19 in human liver microsomes reported in previous studies. SUPERMIX may contain catalytically active CYP2C9 in levels higher than those in human liver microsomes.     

Synthesis of Nanoscale Tips Using Femtosecond Laser Radiation under Ambient Condition

We report a unique growth of platelet-shaped nanoscale tips of transparent dielectric using femtosecond laser radiation at MHz pulse repetition rate with nitrogen background gas flow under ambient condition. The tips grew with sharp nanoscale apex while their base and lengths are of the order of few hundred nanometers. In the absence of nitrogen, the irradiation leads to nanofibrous structure formation. The collision between the nitrogen gas atoms and the vapor species slows down plume expansion and lead to an increase of nanoparticles size. This prevents the fibrous structure formation and provides appropriate condition for nanoscale tips growth.