Study of planar structure applying reciprocity technique combined with MGEC and analysis of discontinuity

The 3D structure electromagnetic computation presents several difficulties related to the volume mesh. In fact, the entire volume space must be taken into account even the smallest details. In this article, we propose a formulation based on the reciprocity theorem combined with the generalized equivalent circuit method to model a planar 3D structure with both coaxial and planar excitation. The major advantage of this formulation is the fact to reduce the computational volume into 2D ones in the discontinuity plane. In addition, we focused on the calculation of the discontinuity between the excitation source and the planar structure to determine the exact behavior of the electric coaxial excitation model. The obtained current density, electric field distributions, and the input impedance are presented and discussed in the following sections. An approximately good agreement of input impedance with those obtained by the simulator and measurement is shown.     

A backbone-reversed all-{beta} polypeptide (retro-CspA) folds and assembles into amyloid nanofibres

The backbone-reversed or ‘retro’, form of a modelall-ß-sheet protein, Escherichia coli CspA, was producedfrom a synthetic gene in E.coli in fusion with an N-terminalaffinity tag. Following purification under denaturing conditionsand dialysis-based removal of urea, the protein was found tofold into a soluble, poorly structured multimer. Upon concentration,this state readily transformed into amyloid nanofibres. CongoRed-binding amorphous forms were also observed. Since a ß-sheet-formingsequence is expected to retain high ß-sheet-formingpropensity even after backbone reversal and given the fact thatfolding of retro-CspA occurs only to a poorly structured form,we conclude that the increase effected in protein concentrationmay be responsible for the formation of intermolecular ß-sheets,facilitating the bleeding away of the protein’s conformationalequilibrium into aggregates that generate well-formed fibres.Since every molecule in these fibres contains a peptide tagfor binding Ni²⁺, the fibres may provide a template for depositionof nickel to generate novel materials. Received April 1, 2003; revised October 27, 2003; accepted October 30, 2003     

Merged BiCMOS logic to extend the CMOS/BiCMOS performance crossoverbelow 2.5-V supply

The authors discuss the merged BiCMOS (MBiCMOS) gate, a unique circuit configuration to improve BiCMOS gate performance at low supply voltages. MBiCMOS maintains a measured delay and power-delay advantage over CMOS into the 2-V supply range, in a simple four-device gate that does not require any change in the standard BiCMOS processing sequence. In a 2-μm technology, MBiCMOS outperforms CMOS down to a 2.6-V supply. Gates designed for fabrication in a 0.5-μm technology and simulated using measured device parameters indicate that MBiCMOS can be used to extend the performance crossover voltage to below 2 V in the submicrometer regime. A full-swing version of the MBiCMOS gate (FS-MBiCMOS) is introduced. Simulations of 2-μm gates show FS-MBiCMOS/CMOS performance crossover voltages of 2.2 V     

Development of methods for evaluating traction fluids

Two methods have been developed for evaluating the performance of potential traction fluids. One method employed a 4-ball machine modified to measure torque and slip under rolling conditions. Aadvantages of the technique were the cheapness and replaceability of the rolling components, and the small amount of test fluid required. The other method was developed using a commercial traction drive, a Kopp variator; it was instrumented to allow measurement of torque and slip. There was a satisfactory correlation between results obtained in both pieces of apparatus for several fluids.Fluids of widely varying compositions were examined in the 4-ball machine and clear indications of the necessary features for a good traction fluid are discussed. In general, fluids with higher pressure-viscosity coefficients were better tractants. There was a clear trend towards better traction with compositions containing high proportions of naphthenic material, an observation which confirmed the patent literature claims for such classes of compounds.     

Synthesis of flexible polymeric shielding materials for soft gamma rays: Physicomechanical and attenuation characteristics of radiation crosslinked polydimethylsiloxane/Bi2O3 composites

Flexible lead‐free high energy radiation shielding material was developed through internal compounding. Polymer‐filler interaction, crosslinking density, specific gravity, physicomechanical characteristics, percentage attenuation, and thermal stability of the crosslinked composites were estimated. It was found that even at very high filler loading composites can be crosslinked; however, the crosslinking density was composition dependent and was highest in 10–50 wt% loading range at 100 kGy and 200 kGy. The Nielsen model was applied to understand the micromechanics of the system. Attenuation of gamma radiation from Am241 was not affected by the crosslinking density. Thermal stability of the composites was found to be significantly affected with bismuth oxide loading. POLYM. COMPOS., 37:756–762, 2016. © 2014 Society of Plastics Engineers     

Dark fermentative biohydrogen production by Acinetobacter junii-AH4 utilizing various industry wastewaters

Hydrogen (H₂) is one of the most promising renewable energy sources, anaerobic bacterial H₂ fermentation is considered as one of the most environmentally sustainable alternatives to meet the potential fossil fuel demand. Bio-H₂ is the cleanest and most effective source of energy provided by the dark fermentation utilizing organic substrates and different wastewaters. In this study, the bio-H₂ production was achieved by using the bacteria Acinetobacter junii-AH4. Further, optimization was carried out at different pH (5.0–8.0) in the presence of wastewaters as substrates (Rice mill wastewater (RMWW), Food wastewater (FWW) and Sugar wastewater (SWW). In this way, the optimized experiments excelled with the maximum cumulative H₂ production of 566.44 ± 3.5 mL/L (100% FWW at pH 7.5) in the presence of Acinetobacter junii-AH4. To achieve this, a bioreactor (3 L) was employed for the effective production of H₂ and Acinetobacter junii-AH4 has shown the highest cumulative H₂ of 613.2 ± 3.0 mL/L, HPR of 8.5 ± 0.4 mL/L/h, HY of 1.8 ± 0.09 mol H₂/mol glucose. Altogether, the present study showed a COD removal efficiency of 79.9 ± 3.5% by utilizing 100% food wastewater at pH 7.5. The modeled data established a batch fermentation system for sustainable H₂ production. This study has aided to achieve an ecofriendly approach using specific wastewaters for the production of bio-H₂.     

Second row transition metal sulfides for the hydrotreatment of coal-derived naphtha I. Catalyst preparation, characterization and comparison of rate of simultaneous removal of total sulfur, nitrogen and oxygen

Naphtha derived from an Illinois No. 6 coal contains appreciable quantities of sulfur-, nitrogen- and oxygen-containing compounds. The hydrotreatment of this naphtha has been evaluated over unsupported transition metal sulfide catalysts of the second row in the Periodic Table. The catalysts were prepared by a room temperature precipitation reaction. Surface areas, crystalline phase and particle size distributions were determined by Brunauer-Emmet-Teller (BET), X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. A comparison of average particle sizes calculated from these three techniques has enabled the understanding of the morphology of the transition metal sulfides. The catalysts exhibit a so-called volcano plot for the HDS of dibenzothiophene. Similar so-called volcano plots are also exhibited for the simultaneous hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and the hydrodeoxygenation (HDO) of the coal-derived naphtha containing a mixture of heteroatoms. The order of reactivity of the transition metal catalysts is the same for all three of the processes. Ruthenium sulfide (RuS₂) is the most active catalyst for HDS, HDN and HDO of the coal-derived naphtha.     

Unusual presentation of a case of Sjogren's syndrome with neurological and ocular manifestation

Sjogren's syndrome is an autoimmune disease that commonly presents to the ophthalmologist as a dry eye disease. We report an unusual presentation of a case of Sjogren's syndrome. A 33-year-old man presented with lid swelling, pseudomembraneous conjunctivitis with central corneal epithelial defect and history of limb weakness for past 2 years. There was progressive enlargement of the epithelial defect and conjunctival-scleral necrosis developed during follow-up. Evaluation for underlying connective tissue disorder was positive for SS-B/La antibody and, the rheumatoid factor, anti nuclear antibody, anti neutrophil cytoplasmic antibody titres were negative. Patient was diagnosed as a case of Primary Sjogren's syndrome. Resolution of the conjunctival-scleral necrosis occurred following treatment with combination of cyclosporine and prednisolone. Paramedian tarsorrhaphy was performed to promote healing of the corneal epithelium. The corneal epithelium healed, conjunctival-scleral necrosis resolved completely and the visual acuity improved to 6/36 in the right eye after 3 months of immunosuppressive therapy. The immunosuppressive therapy was discontinued after completion of 6 months of treatment. After 6 months follow-up of stopping immunosuppressive therapy, the ocular and systemic condition is stable.     

Bio-heat transfer analysis during short pulse laser irradiation of tissues

The objective of this paper is to analyze the temperature distributions and heat affected zone in skin tissue medium when irradiated with either a collimated or a focused laser beam from a short pulse laser source. Experiments are performed on multi-layer tissue phantoms simulating skin tissue with embedded inhomogeneities simulating subsurface tumors and as well as on freshly excised mouse skin tissue samples. Two types of lasers have been used in this study – namely a Q-switched pulsed 1064 nm Nd:YAG short pulse laser having a pulse width of 200 ns and a 1552 nm diode short pulsed laser having a pulse width of 1.3 ps. Experimental measurements of axial and radial temperature distribution in the tissue medium are compared with the numerical modeling results. For numerical modeling, the transient radiative transport equation is first solved using a discrete ordinates method for obtaining the intensity distribution and radiative heat flux inside the tissue medium. Then the temperature distribution is obtained by coupling the bio-heat transfer equation with either hyperbolic non-Fourier or parabolic Fourier heat conduction model. The hyperbolic heat conduction equation is solved using MacCormack’s scheme with error terms correction. It is observed that experimentally measured temperature distribution is in good agreement with that predicted by hyperbolic heat conduction model. The experimental measurements demonstrate that converging laser beam focused directly at the subsurface location can produce desired high temperature at that location compared to that produced by collimated laser beam for the same laser parameters. Finally the ablated tissue removal is characterized using histological studies as a function of laser parameters.     

A discrete damage mechanics model for high cycle fatigue in polycrystalline materials subject to rolling contact

Fatigue behavior of polycrystalline materials is significantly influenced by their microstructural topology. The microstructural heterogeneity is one of the primary reasons for dispersion in high cycle fatigue lives of such materials. In this work, a damage mechanics based fatigue model that incorporates gradual material degradation under cyclic loading is presented in conjunction with a discrete material representation that takes the material microstructural topology into account. Microstructures are generated stochastically through the process of Voronoi tessellation. Micro-crack initiation, coalescence and propagation stages are modeled using damaged zones in a unified framework. The model is applied to study high cycle fatigue in rolling contacts. The effect of material topological disorder and inhomogeneity on fatigue life dispersion is studied. Fatigue damage is found to originate sub-surface and propagate towards the surface. Sub-surface damage patterns from the model are consistent with experimental observations. Propagation life is found to constitute a significant fraction of total life. Lives are found to follow a 3-parameter Weibull distribution. The relative proportion of lives spent in the initiation and propagation stages are in good quantitative agreement with experiments.