Austempered ductile iron (ADI) : influence of austempering temperature on microstructure, mechanical and wear properties and energy consumption

Alloyed Ductile iron austenitized at 840°C for 30 min in a special sealed austempering furnace, was austempered for 30 min in molten salt mixture at 4 trial temperatures of 300 °C, 320 °C, 340 °C and 360°C. Tensile strength, yield strength, percentage elongation and impact energy were evaluated for the as-cast and austempered samples. Microstructures were investigated using microscopy coupled with analyzing software and a scanning electron microscopy. The specific wear of samples was tested using pin-on-disc wear testing machine. X-ray diffraction was performed to calculate the amount of retained austenite present in the ausferrite matrix. As cast microstructure consists of ferrite and pearlite, whereas ADI contains a mixture of acicular ferrite and carbon enriched austenite called “ausferrite”. Hardness and strength decreased, whereas ductility and impact strength improved with increase in austempering temperature. XRD analysis revealed that the increase in austempering temperature increases the retained austenite content. Decrease in wear resistance with austempering temperature was observed. Modified Quality Index (MQI) value was envisaged incorporating tensile strength, elongation and wear resistance. MQI for samples austempered at 340°C and 360°C showed better combination of properties. About 8% reduction in energy consumption is gained when the heat treatment parameters are optimized

On the identity and occurrence of Rubus racemosus (Rosaceae) in India with note on its neotypification

Rubus racemosus is an endemic species of Rosaceae and the distribution is strictly restricted to southern parts of the Western Ghats. The present paper provides a detailed taxonomic description, colour photographs and discusses the taxonomic affinity of the taxon with its allied taxa. And also, the name Rubus racemosus is neotypified here

Effectiveness of cattle and buffalo expert system in knowledge management among the farmers

Present investigation was conducted to assess the effectiveness of cattle and buffalo expert system which was developed under the network project on ‘Development of Expert System for Crop and Animal Enterprises’ with Central Institute for Women in Agriculture (CIWA) as the lead centre. The primary aim of the project was to develop an expert system on cattle and buffalo. The study was carried out to test the effectiveness of developed expert system in terms of knowledge gain and skill acquisition among the 140 farmers who were selected from two villages each from Panamarathupatti and Vazhapadi blocks of Salem district. The snow ball sampling method was used to identify four groups of farmers consisting of marginal and small size dairy farmers, medium size dairy farmers, big dairy farmers and women dairy farmers. The test verified pre and post exposure modules were developed for assessing the respondent’s knowledge gain and skill acquisition behaviour due to cattle and buffalo expert system in cattle. The study showed that medium and large size farmers gained relatively higher knowledge and skill due to their inclination towards undertaking dairy farming on commercial lines as compared to marginal farmers who took up the same at subsistence level in addition to other socio-economic characteristics. The study also brought out constraints and suggestions in improving the usage of expert system among all categories of farmers

Design and Analysis of Composite Leaf Spring

In the present scenario, reducing the weight is the major desire in automobile world. As the conventional steel leaf spring contributes some amount of weight with respect to the total weight of vehicle. So lots of researches are being developed for reduction of weight. This paper deals the reduction of weight in the conventional steel leaf spring with the composite leaf spring. For this purpose various composite materials such as E-glass, epoxy and jute are used in different proportion. This papers also compares the stress, deformation of conventional leaf steel spring with composite leaf spring while loading and unloading, thereby ensuring that the stiffness and efficiency is improved .The three dimensional model are analyzed in CATIA V5R20 and Ansys

Quantum Dots for Live Cell and In Vivo Imaging

In the past few decades, technology has made immeasurable strides to enable visualization, identification, and quantitation in biological systems. Many of these technological advancements are occurring on the nanometer scale, where multiple scientific disciplines are combining to create new materials with enhanced properties. The integration of inorganic synthetic methods with a size reduction to the nano-scale has lead to the creation of a new class of optical reporters, called quantum dots. These semiconductor quantum dot nanocrystals have emerged as an alternative to organic dyes and fluorescent proteins, and are brighter and more stable against photobleaching than standard fluorescent indicators. Quantum dots have tunable optical properties that have proved useful in a wide range of applications from multiplexed analysis such as DNA detection and cell sorting and tracking, to most recently demonstrating promise for in vivo imaging and diagnostics. This review provides an in-depth discussion of past, present, and future trends in quantum dot use with an emphasis on in vivo imaging and its related applications

Recrystallization kinetic study of copper-bearing strip cast steels

The effects of copper on as-cast structure, recrystallization and precipitation kinetics of strip cast low carbon steel were investigated. As-cast microstructure mainly consists of polygonal ferrite and Widmanstatten ferrite. Recrystallization responses were strongly dependent on initial microstructure and Cu content. Precipitation strengthening was observed in high copper content alloys

DEVELOPMENT OF PERMEABLE REACTIVE FILTER SYSTEMS (PRFS) FOR TREATMENT OF URBAN STORMWATER RUNOFF

Urban stormwater runoff is a major contributor of pollutants to nearshore beach water of Lake Michigan and other water bodies. Reduction of pollutants levels to within safe limits in urban runoff from near shore areas by means of filtration using low-impact reactive multi-media systems is the subject of research in this dissertation. The key research issues addressed are the identification of effective filter materials and laboratory-scale testing of the selected materials for permeable reactive filter systems (PRFS) that are feasible for installation in urban environment. The focus was to evaluate different media materials for removal of total suspended solids (TSS), nutrients (nitrate and phosphate), heavy metals (Cd, Cr, Cu, Pb, Ni and Zn), polycyclic aromatic hydrocarbons (naphthalene and phenanthrene) and microbial (E. coli.) contaminants from stormwater runoff to levels below standard discharge criteria. Eight different media materials were initially selected, including calcite, anthracite coal, zeolite, sand, iron-oxide coated sand (IOCS), iron filings, perlite and biochar. Of these, calcite (C), zeolite (Z), sand (S) and iron filings (Fe0) were screened based on preliminary column experiment results and used for further studies. Physical and chemical characterization studies were carried out to understand the material properties. Contaminant attenuation studies with lab-scale column experiments for the four individual media materials (C, Z, S and Fe0) were conducted with synthetic stormwater solution containing all the aforementioned pollutants. Results showed that calcite and sand were efficient in TSS, nutrients and polycyclic aromatic hydrocarbons (PAHs) removal, zeolite was efficient for metals removal and the only material that was able to lower E. coli level to below its safe xv limit of 126 most probable number (MPN) per 100ml, and iron filings was efficient in nutrients and metals removal. Column experiments were also conducted with three mixed media compositions, C-Z-S, C-Z-Fe0 and C-Z-S-Fe0. The results indicated that a multi-media based filtration system can perform efficiently to treat a wide range of pollutants and runoff flow conditions. Finally, several conceptual designs for PRFS were proposed that are suitable for application at various urban locations.PH.D in Environmental Engineering, May 201

Inverse Design of Plasmonic Nano-Antenna

We develop a new method for inverse design of plasmonic nano-antennas. We demonstrate the accuracy of this method for a plasmonic antenna used for heat-assisted magnetic recording (HAMR). We also use non-linear material interpolation to counter the non-physical field amplification, and filtering-and-projection regularization to ensure manufacturability of the design. Successful design of a plasmonic aperture to produce an electric field as small as 60 nm x 30 nm is presented