Fabrication of Multi-Layered Zn-Fe Alloy Coatings for Better Corrosion Performance

Zn-Fe compositionally modulated multilayer alloy (CMMA) coatings were developed onto low carbon steel from acid sulphate bath; and their corrosion resistance was calculated using Tafel polarization and impedance methods. The deposit layers were formed galvanostatically by single bath technique (SBT), using square current pulses. An optimal configuration for the growth of most corrosion resistant Zn-Fe coating was proposed and discussed. At maximum switching cathode current density (SCCD) (2.0–5.0 A dm−2), the deposit with 300 layers showed ~43 times superior corrosion resistance than the same thickness of monolayer coating. The improved corrosion resistance of multilayered coatings is due to small change in iron content, leading to change the phase structure of the alternate-layers of the alloy coatings. The surface morphology and structure of film and roughness of the deposit were assessed using Scanning Electron Microscopy and Atomic Force Microscopy. Thus, superior corrosion resistance of Zn-Fe multilayer coatings was used for industrial applications including defense, machinery and automobile etc

Stylo in India: Much More Than a Plant for the Revegetation of Wasteland

Since the 1950s introductions of Stylosanthes scabra, S. hamata and S. guianensis from Australia, South America, the USA and Africa have continued in India. Although no cultivar has been released, selections of S. scabra, S guianensis and S. hamata are used in a range of environmental and commercial production systems. A large seed industry spanning \u3e400 ha and run by \u3e600 smallholder farmers producing 800t seeds/ year supports this usage (Rao et al., 2004). Stylo is mainly used in India for revegetation of wastelands where it reduces soil erosion and offers fodder for livestock (Pathak et al., 2004). Relatively small use is made as supplementary feed for dairy and breeding farms, as pastures in sheep and goat farms, in urban forestry and as a cover crop in horticulture and agroforestry. There are probably some 20,000 ha under silvipasture and horticulture. In mixed crop-livestock farming system stylo has been a saviour for smallholder farmers in some arid areas. The recent success of S. seabrana as a multipurpose legume and the suitability of stylo leaf meal as a replacement for expensive constituents in commercial poultry feed formulations may further accelerate uptake

Design and Implementation of C-Band Frequency Synthesizer Using LMX2592 IC

The paper presents the design scheme and implementation of a PLL-based-frequency synthesizer using LMX2592 IC. The frequency synthesizer have vital role in the development of up-converter and down-converter equipments. Therefore, on the RT-Duroid RO4350 substrate, a low phase noise and stable carrier generator is designed and implemented. Graphical User Interface (GUI) & LAN based programming is developed to easily change the synthesizer frequency. The control system analysis using root locus and bode plot is presented for system stability. The experimental results representing the performance parameters, like frequency range, frequency step size, output power, phase noise, carrier stability, harmonics, and spurious, etc., are also presented in the paper. The analysis of spurious and phase noise performance at near integer boundary conditions are done by changing loop bandwidth and phase margin.&nbsp

Soil Biological Activity Contributing to Phosphorus Availability in Vertisols under Long-Term Organic and Conventional Agricultural Management

Mobilization of unavailable phosphorus (P) to plant available P is a prerequisite to sustain crop productivity. Although most of the agricultural soils have sufficient amounts of phosphorus, low availability of native soil P remains a key limiting factor to increasing crop productivity. Solubilization and mineralization of applied and native P to plant available form is mediated through a number of biological and biochemical processes that are strongly influenced by soil carbon/organic matter, besides other biotic and abiotic factors. Soils rich in organic matter are expected to have higher P availability potentially due to higher biological activity. In conventional agricultural systems mineral fertilizers are used to supply P for plant growth, whereas organic systems largely rely on inputs of organic origin. The soils under organic management are supposed to be biologically more active and thus possess a higher capability to mobilize native or applied P. In this study we compared biological activity in soil of a long-term farming systems comparison field trial in vertisols under a subtropical (semi-arid) environment. Soil samples were collected from plots under 7 years of organic and conventional management at five different time points in soybean (Glycine max) -wheat (Triticum aestivum) crop sequence including the crop growth stages of reproductive significance. Upon analysis of various soil biological properties such as dehydrogenase, β-glucosidase, acid and alkaline phosphatase activities, microbial respiration, substrate induced respiration, soil microbial biomass carbon, organically managed soils were found to be biologically more active particularly at R2 stage in soybean and panicle initiation stage in wheat. We also determined the synergies between these biological parameters by using the methodology of principle component analysis. At all sampling points, P availability in organic and conventional systems was comparable. Our findings clearly indicate that owing to higher biological activity, organic systems possess equal capabilities of supplying P for crop growth as are conventional systems with inputs of mineral P fertilizers

Bright Giant Pulses from the Crab Nebula Pulsar: Statistical Properties, Pulse Broadening and Scattering due to the Nebula

We report observations of Crab giant pulses made with the Australia Telescope Compact Array and a baseband recorder system, made simultaneously at two frequencies, 1300 and 1470 MHz. These observations were sensitive to pulses with amplitudes \ga 3 kJy and widths \ga 0.5 $\mu$s. Our analysis led to the detection of more than 700 such bright giant pulses over 3 hours, and using this large sample we investigate their amplitude, width, arrival time and energy distributions. The brightest pulse detected in our data has a peak amplitude of $\sim$ 45 kJy and a width of $\sim$ 0.5 $\mu$s, and therefore an inferred brightness temperature of $\sim 10^{35}$ K. The duration of giant-pulse emission is typically $\sim$1 $\mu$s, however it can also be as long as 10 $\mu$s. The pulse shape at a high time resolution (128 ns) shows rich diversity and complexity in structure and is marked by an unusually low degree of scattering. We discuss possible implications for scattering due to the nebula, and for underlying structures and electron densities.Comment: 8 pages, 8 figures, Accepted for publication in Ap

The Flavonoid Metabolite 2,4,6-Trihydroxybenzoic Acid Is a CDK Inhibitor and an Anti-Proliferative Agent: A Potential Role in Cancer Prevention

Flavonoids have emerged as promising compounds capable of preventing colorectal cancer (CRC) due to their anti-oxidant and anti-inflammatory properties. It is hypothesized that the metabolites of flavonoids are primarily responsible for the observed anti-cancer effects owing to the unstable nature of the parent compounds and their degradation by colonic microflora. In this study, we investigated the ability of one metabolite, 2,4,6-trihydroxybenzoic acid (2,4,6-THBA) to inhibit Cyclin Dependent Kinase (CDK) activity and cancer cell proliferation. Using in vitro kinase assays, we demonstrated that 2,4,6-THBA dose-dependently inhibited CDKs 1, 2 and 4 and in silico studies identified key amino acids involved in these interactions. Interestingly, no significant CDK inhibition was observed with the structurally related compounds 3,4,5-trihydroxybenzoic acid (3,4,5-THBA) and phloroglucinol, suggesting that orientation of the functional groups and specific amino acid interactions may play a role in inhibition. We showed that cellular uptake of 2,4,6-THBA required the expression of functional SLC5A8, a monocarboxylic acid transporter. Consistent with this, in cells expressing functional SLC5A8, 2,4,6-THBA induced CDK inhibitory proteins p21Cip1 and p27Kip1 and inhibited cell proliferation. These findings, for the first time, suggest that the flavonoid metabolite 2,4,6-THBA may mediate its effects through a CDK- and SLC5A8-dependent pathway contributing to the prevention of CRC

Detection of Crab Giant Pulses Using the Mileura Widefield Array Low Frequency Demonstrator Field Prototype System

We report on the detection of giant pulses from the Crab Nebula pulsar at a frequency of 200 MHz using the field deployment system designed for the Mileura Widefield Array's Low Frequency Demonstrator (MWA-LFD). Our observations are among the first high-quality detections at such low frequencies. The measured pulse shapes are deconvolved for interstellar pulse broadening, yielding a pulse-broadening time of 670$\pm$100 $\mu$s, and the implied strength of scattering (scattering measure) is the lowest that is estimated towards the Crab nebula from observations made so far. The sensitivity of the system is largely dictated by the sky background, and our simple equipment is capable of detecting pulses that are brighter than $\sim$9 kJy in amplitude. The brightest giant pulse detected in our data has a peak amplitude of $\sim$50 kJy, and the implied brightness temperature is $10^{31.6}$ K. We discuss the giant pulse detection prospects with the full MWA-LFD system. With a sensitivity over two orders of magnitude larger than the prototype equipment, the full system will be capable of detecting such bright giant pulses out to a wide range of Galactic distances; from $\sim$8 to $\sim$30 kpc depending on the frequency. The MWA-LFD will thus be a highly promising instrument for the studies of giant pulses and other fast radio transients at low frequencies.Comment: 10 pages, 6 figures, Accepted for publication in the Astrophysical Journa