Characterization of friction surfaced martensitic stainless steel (AISI 410) coatings

Friction surfacing is a candidate process for depositing corrosion and wear resistant coatings. Being a solid-state process, it offers several advantages over conventional fusion welding based surfacing process. In the current work, martensitic stainless steel AISI 410 was friction surfaced over mild steel substrates. Coating microstructures were characterized using light microscopy, scanning electron microscopy and Xray diffraction. Coatings in as-deposited condition exhibited a fully martensitic microstructure and were found to be quite hard (with an average hardness of 460 HV). Bend and shear tests indicated excellent coating/substrate bonding. Overall, the current work shows that martensitic stainless steel AISI 410 can be satisfactorily friction surfaced on mild steel.     

Economic feasibility of electricity production from energy plantations present on community-managed forestlands in Madhya Pradesh,India

This paper assesses economic feasibility of utilizing community-managed degraded forest areas for raising energy crops and using the produced biomass for electricity production in the state of Madhya Pradesh, India through gasification technology. Three fast-growing species, three gasifiers of different capacities, three capital costs, and two scenarios of carbon payments were considered for analysis. Sensitivity and risk analyses were undertaken for determining the effects of variations in inputs on selected outputs. Results suggest that 5 million megawatt hour electricity can be generated annually which will prevent 4 million tons of carbon dioxide emissions per year. The production cost of a unit of electricity was found inversely related to the scale of production. The average cost of electricity at the consumer level produced using 100 kW gasifier was $0.15/kWh, which was greater than the price of electricity supplied from grid i.e. $0.08/kWh. The unit cost of producing electricity using Acacia nilotica was lowest among all the selected species. Technological advancements suitable government incentives are needed to promote electricity generation from forest biomass through gasification technology. This will help in spurring economic development and reducing overall ecological footprint of the state.     

Anthranilamide-pyrazolo[1,5-a]pyrimidine conjugates as p53 activators in cervical cancer cells

A library of new anthranilamide-pyrazolo[1,5-a]pyrimidine conjugates were designed, synthesized, and evaluated for their anticancer activity in cervical cancer cells such as HeLa and SiHa that possess low levels of p53. All 24 conjugates showed antiproliferative activity, while some of them exhibit significant cytotoxicity. In assays related to cell-cycle distribution, these conjugates induced G(2) /M arrest in HeLa cells and G(1) cell-cycle arrest in SiHa cells. Immunocytochemistry assays revealed that these compounds cause nuclear translocation of p53, thereby indicating the activation of p53. In cervical cancer cells, the p53 protein is degraded by E6 oncoprotein. Immunoblot and RT-PCR analyses proved the presence of mitochondria-mediated apoptosis with involvement p53 target genes such as BAX, Bcl2, and p21 (CDKI). Moreover, these compounds increased the phosphorylated forms of p53 and provide signals for apoptosis induction. Interestingly, one of the conjugates, (2-phenyl-7-(3,4,5-trimethoxyphenyl)pyrazolo[1,5-a]pyrimidin-5-yl)(4-(2-(thiophen-2-ylmethylamino)benzoyl)piperazin-1-yl)methanone, is the most promising candidate in this series and has the potential to be taken up for further detailed studies.     

Evaluation of performance of water quality models for a tropical lake system

The ability to predict water quality is a major requirement for planning and execution of developmental projects. It helps entrepreneurs to effectively plan and implement pollution control measures. This study evaluates the ability of different water quality models (statistical; remote sensing; mathematical) to predict salinity in Akkulam–Veli Lake, a tropical lake system. The performance of these three water quality models was evaluated. Prediction of salinity was made accurately with the mathematical model (WASP), compared to the other models. WASP facilitates prediction of daily water quality variations, which is not possible with the other models. A limitation of this model, however, was its ability to predict only a few water quality parameters. The statistical methods are reliable when the number of sampling sites and frequency of sample collection are high, making this method exhaustive and expensive. Remote sensing techniques proved to be less tedious, but are suitable only under specific situations, and not able to produce a high level of accuracy. Nevertheless, this method provides a continuous picture of spatial variations of different water quality parameters to a reasonable level of accuracy. The choice of the ‘best’ model varies on the basis of climatic and field conditions of the lake system of concern. Thus, a combination of water quality models was found to be the most ideal approach for analysing water quality data.     

Interface shear characteristics of jute/polypropylene hybrid nonwoven geotextiles and sand using large size direct shear test

In this study, large-size direct shear tests were conducted to determine the interfacial shear characteristics of sand–geotextile under three different normal stresses. The geotextiles used in the present study were hybrid needlepunched nonwovens containing defined weight proportions of jute and polypropylene fibers. Subsequently, the interfacial shear characteristics of hybrid and that of a nonwoven geotextile consisting of solely polypropylene fibers with sand were compared and analyzed under different normal stresses. Initial higher shear stiffness of sand-polypropylene geotextiles was observed corresponding to sand-hybrid geotextiles specifically under higher normal stresses. Nevertheless, the contact efficiency of sand-hybrid nonwovens was similar to that of sand-polypropylene geotextiles. The surface morphology of sand particles has been investigated based on the images obtained from scanning electron microscopy (SEM) and quantitatively analyzed by means of Wadell roundness and degree of angularity methods.     

Lake bathymetry from Indian Remote Sensing (P6‐LISS III) satellite imagery using artificial neural network model

The remote sensing technique provides a rapid and relatively inexpensive means of identifying silted areas in large water bodies, in order that desilting activities can be effectively conducted. This study developed lake bathymetry for a selected lake system (Akkulam–Veli Lake, Kerala, India) from the Indian Remote Sensing (IRS P6‐LISS III) satellite imagery, using an artificial neural network (ANN) model. The water depth was measured for 17 months at different points in the lake on the same date of overpass of the IRS satellite. The satellite imageries obtained for 12 December 2007 and 16 February 2009 were identified as cloud‐free images. ANN models were developed with the four input series of radiance values from green, red, NIR and MIR bands observed for the satellite imagery obtained on 12 December 2007 at the sampling sites, with actual water depth measurements also being taken on the same date. A three‐layered feed forward neural network with back propagation training algorithm was developed for this study. To train the model, it was run several times by changing the number of neurons, learning rate and the momentum constants until the mean square error was minimum. When the number of neurons is increased to 35, and the logsig function is used as ANN transfer function, the error becomes minimum. To test the model, the developed ANN was run for a new set of input from the satellite imagery taken on 16 February 2009. Comparing the predicted and measured values for the same sites for the same day, it was found that the model is best suited for predicting water depth using ANN and the radiance values for four bands of IRS satellite imagery. The results of this study indicated that, for the shallow lake with lower depth, the difference between the actual and predicted value was considerable. In contrast, this was not the case where the lake water depth was greater, indicating an increased prediction accuracy with ANN with increasing depths for shallow lakes. A bathymetry map prepared with ANN indicated only the lake shoreline, as well as the shallow littoral zones. The approach used in this study requires further refinement, including further of the model based on using more field measurements to obtain a better bathymetry map.     

Solidification and Liquation Cracking Behavior of Dual-Phase Steel DP600

Metallurgical and Materials Transactions B - In this work, the solidification and liquation cracking behavior of a dual-phase steel DP600 was examined using longitudinal Varestraint testing and hot...     

Microstructure and wear properties of LENS<Superscript>® </Superscript>deposited medical grade CoCrMo

There is a growing interest in metal-on-metal bearing surfaces for orthopedic implants. Although some success has been achieved in applications like hip implants which involve a large contact area, non-conforming joints, such as knees, have proved more difficult. The current work examines the applicability of a novel additive manufacturing process, Laser Engineered Net Shaping (LENS), the registered trademark and service mark of Sandia National Laboratories and Sandia Corporation), for producing CoCrMo implants. A series of experiments were conducted to determine the optimum parameters for deposition of CoCrMo. Microstructural studies, hardness tests, and dry sand/rubber wheel abrasive wear tests were conducted on the LENS deposits. The results showed that metallurgically sound deposits can be produced using the LENS process under optimized conditions. The hardness of the LENS deposited CoCrMo was found to be comparable to that of standard CoCrMo wrought material; however, wear tests indicated that LENS deposits were considerably less resistant to abrasive wear than wrought CoCrMo. The reasons for this behaviour are discussed based on microstructural observations.     

Reaction Kinetics at the Fiber/Matrix Interface of SiC<Subscript>f</Subscript>/Ti–15–3 Composites

In the current research work, spark plasma consolidated beta-titanium alloy Ti–15V–3Cr–3Al–3Sn composites reinforced with SiC fibers (Sigma SM1240) were subjected to high temperatures (1173, 1223 and 1273 K) for different time periods (2.7, 11, 25 and 44 h) to investigate the kinetics of the chemical reactions at the fiber/matrix interface. Through microstructural studies and room temperature tensile tests, we have attempted to study the effect of the formed brittle reaction zone on the final mechanical properties of the composite. We have observed that, prior to the SiC fiber, the protective carbon coating reacts with the matrix and results in the formation of a reaction zone (predominantly TiC) at the fiber/matrix interface. The reaction zone propagates into the matrix with increase in time at the expense of the carbon coating, and finally ends with the onset of titanium silicide reaction. The reaction kinetics at the fiber/matrix interface was predominantly controlled by diffusion of carbon through the reaction zone and the activation energy for the same was calculated to be 149 kJ/mol. It was clear from the tensile test results that the mechanical properties of the composites do not earnestly decrease until the commencement of titanium silicide reaction.