Chemical composition and antifungal activity of essential oils from three Himalayan Erigeron species

Three Himalayan Erigeron (Asteraceae) species viz Erigeron mucronatus, Erigeron annuus and Erigeron karwinskianus growing in sub-alpine region revealed occurrence of isomeric polyacetylenic constituents viz., matricaria and lachnophyllum esters which accounted for 83.3%, 69.3% and 30.1% of the essential oils from these species, respectively, in addition to mono- and sesquiterpenoids as minor constituents. The antifungal activity tested by poisoned food (PF) techniques against Fusarium oxysporum, Helminthosporium maydis, Rhizoctonia solani, Alternaria solani and Sclerotinia sclerotiorum demonstrated significant inhibition of the mycelial growth of all strains (p < 0.05). The oils (500 μg/mL) showed significant antifungal effect against tested fungi in the growth inhibition range of 37.6–85.5% with respective IC₅₀ values ranging from 88.8 to 660.0 μg/mL as compared to standard fungicides (100% inhibition) with IC₅₀ value in the range of 32.2–129.4 μg/mL. Significant inhibition of spore germination was noticed for F. oxysporum, Curvularia lunata and Albugo candida which were highly susceptible to E. annuus oil with their IC₅₀ values 120.7, 253.5 and 300.4 μg/mL, respectively. Thus, the results obtained in this study demonstrate the potential of essential oils from Himalayan Erigeron species as non-toxic, eco-friendly and biodegradable natural fungicides.     

印度印刷业概况

在过去的15年内，印度印刷业发生了天翻地覆的变化。1990年，印度发起了一场破除贸易壁垒，实现经济自由化的改革。为了使印度经济与全球经济更好地融合，印度加快了推进私人化的进程。在这场改革中，许多印度印刷企业开始引进最新的技术和设备，这也为印度印刷业打开了通向现代化的大门。在过去的15年中，印度的年平均综合增长速度超过了12％，而包装行业目前更是达到超过16％的增长速度。     

Effect of silicate adsorption on the double layer capacitance and exchange current density of the Pb/PbSO4 electrode reaction

Galvanostatic transients in the linear polarization domain have been used to analyse the variation of double layer capacitance and exchange current densities of the Pb/PbSO₄ electrode reaction at various states-of-charge (SOC) values. From these data, the potential-dependence of double layer capacitance has been evaluated as a function of SOC. Interesting changes have been observed in the double-layer capacitance and exchange current densities as a result of immobilization of the electrolyte.     

Fabrication of low defect density 3C-SiC on SiO2 structures using wafer bonding techniques

This paper reports on a process to fabricate single-crystal 3C-SiC on SiO₂ structures using a wafer bonding technique. The process uses the bonding of two polished polysilicon surfaces as a means to transfer a heteroepitaxial 3C-SiC film grown on a Si wafer to a thermally oxidized Si wafer. Transfer yields of up to 80% for 4 inch diameter 3C-SiC films have been achieved. Homoepitaxial 3C-SiC films grown on the 3C-SiC on SiO₂ structures have a much lower defect density than conventional 3C-SiC on Si films.     

Synthesis and characterization of alumina-coated carbon nanotubes and their application for lead removal

Alumina-coated multi-wall carbon nanotubes were synthesized and characterized by scanning electron microscopy, X-ray diffraction, and FTIR. They were used as an adsorbent for the removal of lead ions from aqueous solutions in two modes, batch and fixed bed. In the batch mode, experiments were carried out to investigate the effect of contact time, agitation speed, adsorbent dosage and solution pH on the removal of lead. The coated nanotubes exhibit better removal ability over uncoated. For fixed-bed columns, thickness of the layer and flow rate were investigated. Increasing the thickness and decreasing the flow rate enhanced the removal of lead. The prepared adsorbent displayed the main advantage of separation convenience when a fixed-bed column was used compared to the batch adsorption treatment.     

Gate Current Modeling and Optimal Design of Nanoscale Non-Overlapped Gate to Source/Drain MOSFET

In this paper, novel nanoscale MOSFET with Source/Drain-to-Gate Non-overlapped and high-k spacer structure has been demonstrated to reduce the gate leakage current for the first time. The gate leakage behaviour of novel MOSFET structure has been investigated with help of compact analytical model and Sentaurus Simulation. Fringing gate electric field through the dielectric spacer induces inversion layer in the non-overlap region to act as extended S/D region. It is found that optimal Source/Drain-to-Gate Non-overlapped and high-k spacer structure has reduced the gate leakage current to great extent as compared to those of an overlapped structure. Further, the proposed structure had improved off current, subthreshold slope and DIBL characteristic. It is concluded that this structure solves the problem of high leakage current without introducing the extra series resistance.     

A New Flexible Filter Bank for Low Complexity Spectrum Sensing in Cognitive Radios

Conventional filter bank-based spectrum sensing methods employ uniform discrete Fourier transform filter bank (DFTFB). In this paper, we propose a multi-stage coefficient decimation filter bank (MS-CDFB) for wideband spectrum sensing in cognitive radios. From an initial fixed-coefficient modal filter, a filter bank that has multiple passbands of either uniform or different passband widths can be obtained using coefficient decimation. Design examples show that proposed MS-CDFB offers a complexity reduction of about 30% over the DFTFB while giving a superior sensing accuracy than the latter. The complexity reduction of MS-CDFB over the DFTFB is 85%, if both the spectrum sensors are designed to produce identical sensing accuracies.     

Combined addition of nano diamond and nano SiO2, an effective method to improve the in-field critical current density of MgB2 superconductor

MgB₂ bulk samples added with nano SiO₂ and/or nano diamond were prepared by powder-in-sealed-tube (PIST) method and the effects of addition on structural and superconducting properties were studied. X-ray diffraction (XRD) analysis revealed that the addition caused systematic reduction in ‘a’ lattice parameter due to the substitution of C atoms at B sites and the strain caused by reacted intragrain nano particles of Mg₂Si as evinced by transmission electron microscope image. Scanning electron microscopy images showed distinct microstructural variations with SiO₂/diamond addition. It was evident from DC magnetization measurements that the in-field critical current density [J_C(H)] of doped samples did not fall drastically like the undoped sample. Among the doped samples the J_C(H) of co-doped samples were significantly higher and the best co-doped sample yielded a J_C, an order of magnitude more than the undoped one at 5 K and 8 T.     

Experimental Investigation of Ultrasonic Machining of an Alumina-Based Ceramic Composite

The aim of this article is to present the ultrasonic machining of an alumina-based engineering ceramic composite. The machining mechanism and the behavior of certain tool material and work material combinations with respect to penetration rate and tool-wear rate under the influence of different parameters in ultrasonic machining are discussed in this paper. The shocking movement and cutting mechanics of the abrasive particle under the tip of the vibrating tool have been observed using high-speed photographic equipment. The machined surface has been analyzed by using a scanning electron microscope. Surface roughness values were measured and plotted at entry and at exit of the holes for different types and sizes of holes using the surface roughness-measuring instrument "Perthometer."