Influence of Microalloying and Isothermal Treatment on Microstructure and Mechanical Properties of High Carbon Steel

Indrajit Dey,Rajib Saha,Swarup Kumar Ghosh 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The influence of isothermal holding (IH) near the pearlite start temperature (Ps≈610 °C) and above the martensite starttemperature (Ms≈245 °C) were studied in two hot-rolled (FRT≈1000 °C) high carbon steels, without (HC0) and with Nbmicroalloying (HC1). Optical microscopy (OM), field emission scanning electron microscopy (FESEM) and high-resolutiontransmission electron microscopy (HRTEM) were utilised for observing the microstructural constituents whereas, nanoindentationand microindentation were performed to estimate the average hardness and elastic modulus values of various phaseconstituents. It has been observed that hot deformation in the austenite region results in the formation of a dual phase-typemicrostructure consisting of fine pearlite lamella and ferrite grains with some amount of degenerated pearlite. IH at 570 °Cleads to a higher volume percentage of ferrite and coarsening of pearlite whereas, IH at 300 °C results in mixed phases comprisingbainite, a very low amount of martensite/retained austenite (M/RA), pearlite and some amount of ferrite. Hot rolledmicroalloyed steel when isothermally held near the Psresults in a significant enhancement of ductility than hot rolled andair-cooled condition while sacrificing tensile strength marginally, which may be attributed to a higher percentage of ferriteand refinement of pearlite due to Nb addition. The estimated yield strength values correlate well with those experimentalyield strength values, but a little discrepancy has been noticed for the ultimate tensile strength values. Possible interpretationsare suggested in this paper.

Maximum Scour Depth at Piers in Armor-Beds

Rajkumar V. Raikar,Subhasish Dey 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.2

The paper presents a design method to determine the maximum equilibrium scour depth at piers embedded in a sand-bed overlain by a thin armor-layer of gravels using the experimental data of Dey and Raikar and those of Ettema. The proposed equation is in terms of empirical relationships, termed K-factors, which account for the effects of flow depth, pier shape, flow intensity, bed sediment size and armor gravel size on scour depth for individual cases of scour holes as identified by Dey and Raikar. These Kfactors are determined by fitting envelope curves to the experimental data. The estimated largest possible scour depths that can occur at circular and square piers with an armor-layer are 3.15 and 3.47 times the pier width, respectively. The paper presents a design method to determine the maximum equilibrium scour depth at piers embedded in a sand-bed overlain by a thin armor-layer of gravels using the experimental data of Dey and Raikar and those of Ettema. The proposed equation is in terms of empirical relationships, termed K-factors, which account for the effects of flow depth, pier shape, flow intensity, bed sediment size and armor gravel size on scour depth for individual cases of scour holes as identified by Dey and Raikar. These Kfactors are determined by fitting envelope curves to the experimental data. The estimated largest possible scour depths that can occur at circular and square piers with an armor-layer are 3.15 and 3.47 times the pier width, respectively.

Application of Multivariate Adaptive Regression Spline-Assisted Objective Function on Optimization of Heat Transfer Rate Around a Cylinder

Prasenjit Dey,Ajoy K. Das 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.6

The present study aims to predict the heat transfer characteristics around a square cylinderwith different corner radii using multivariate adaptive regression splines (MARS). Further, the MARS-generated objective function is optimized by particle swarm optimization. The data for the prediction are taken from the recently published article by thepresent authors [P. Dey, A. Sarkar, A.K. Das, Development of GEP and ANN model to predictthe unsteady forced convection over a cylinder, Neural Comput. Appl. (2015) 1-13]. Further,the MARS model is compared with artificial neural network and gene expression programming. It has been found that the MARS model is very efficient in predicting the heattransfer characteristics. It has also been found that MARS is more efficient than artificialneural network and gene expression programming in predicting the forced convectiondata, and also particle swarm optimization can efficiently optimize the heat transfer rate.

Perception on Impact of Climate Change on Forest Ecosystem in Protected Area of West Bengal, India

Dey, Tanusri,Pala, Nazir A.,Shukla, Gopal,Pal, Prabhat K.,Chakravarty, Sumit Institute of Forest Science 2017 Journal of Forest Science Vol.33 No.1

In the present exploration we identified perception of forest dependent communities in relation to impact of climate change on forest ecosystem in and around Chilapatta reserve forest in northern part of West Bengal, India. Purposive sampling method was used for selection of area and random sampling method was used for selection of respondent. The data collection in this study was through questionnaire based personal in-depth interviews. Almost all the respondents (94%) were farmers and rest had occupation other than farming. Almost all the respondents perceived negative impact of climate change on forest though the level of perception varies from very low to medium (0.23-0.52) based on average perception score after assigning score to individual statements. The level of perception on impact of climate change on forest ecology and forest flora of the community is low and very low as the average perception score is 0.39 and 0.23, respectively while, it is medium (0.52) for forest fauna. Alternately their perception on decreased stream/river flow and quick drying of seasonal streams or water bodies is based on their livelihood experience as they depend on these for their domestic and irrigation water use and fish catch for family diet.

Black gram (Vigna Mungo L.) foliage supplementation to crossbred cows: effects on feed intake, nutrient digestibility and milk production

Dey, Avijit,De, Partha Sarathi,Gangopadhyay, Prabir Kumar Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.2

Objective: An experiment was conducted to examine the effect of dietary supplementation of dried and ground foliage of black gram (Vigna mungo L.) on feed intake and utilization, and production performance of crossbred lactating cows. Methods: Eighteen lactating crossbred (Bos taurus${\times}$Bos indicus) cows (body weight $330.93{\pm}10.82kg$) at their second and mid lactation (milk yield $6.77{\pm}0.54kg/d$) were randomly divided into three groups of six each in a completely randomized block design. Three supplements were formulated by quantitatively replacing 0, 50, and 100 per cent of dietary wheat bran of concentrate mixture with dried and ground foliage of black gram. The designated supplement was fed to each group with basal diet of rice straw (ad libitum) to meet the requirements for maintenance and milk production. Daily feed intake and milk yield was recorded. A digestion trial was conducted to determine the total tract digestibility of various nutrients. Results: The daily feed intake was increased (p<0.05) with the supplementation of black gram foliage. Although the digestibility of dry matter, organic matter, crude protein, and ether extract did not vary (p>0.05), the fibre digestibility was increased (p<0.05), which ultimately improved (p<0.05) the total digestible nutrients content of composite diet. Although, the average milk yield (kg/animal/d) and composition did not differ (p>0.05) among the groups, milk yield was increased by 10 per cent with total replacement of wheat bran in concentrate mixture with of black gram foliage. The economics of milk production calculated as feed cost per kg milk yield (INR 10.61 vs 7.98) was reduced by complete replacement of wheat bran with black gram foliage. Conclusion: Black gram foliage could be used as complete replacement for wheat bran in concentrate mixture of dairy cows in formulating least cost ration for economic milk production in small holders' animal production.

Diversity of Natural Enemies of Aphids Belonging to Aphidiinae (Hymenoptera: Braconidae) in India

Dey, Debjani,Akhtar, Mir Samim Korean Society of Applied Entomology 2007 Journal of Asia-Pacific Entomology Vol.10 No.4

An inventory of the biodiversity of aphidiine parasitoids (Hymenoptera: Braconidae) associated with aphids in India showed 123 species under 23 genera to be intensively and extensively exercising natural control. The inventory has been reinforced with all associated details, mainly zoogeographical distribution, parasitism potential attributes and other such relative details from primary sources so as to make it serve as an important startup tool for planning any IPM strategy, involving biocontrol of aphids.

A Realistic Approach Towards Solution of Load Frequency Control Problem in Interconnected Power Systems

Dey Prasenjit,Saha Anulekha,Srimannarayana Poluri,Bhattacharya Aniruddha,Marungsri Boonruang 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2

This paper attempts to identify the diff erent issues related to frequency oscillations in power systems and off ers newer and reliable approach to mitigate them. Load frequency control (LFC) is important to identify the error pertaining to tie-line power exchange in multi-area power systems. A practical system calls for a robust LFC system to handle variations of diff erent parameters owing to load variations. Classical LFC models available in the literature approaches this LFC problem based only on turbine inputs and swing equation and does not consider other important parameters such as stator currents, fi eld voltages, damper winding voltages and network equations etc., which renders the existing models impractical. This paper introduces detailed model using equation based LFC that considers the above parameters and has been implemented on both single and multi-area power systems for validation. For multi-area interconnected power system network, LFC is introduced considering area interchange control (AIC) concept. Integral (I), Integral derivative (ID) and proportional integral derivative (PID), controllers are used to mitigate the frequency oscillations as well as tie-line power deviation between diff erent areas. Three diff erent meta-heuristic algorithms, namely: Salp swarm algorithms (SSA), Grasshopper optimization algorithm (GOA), Collective decision optimization algorithm (CDO) have been employed to tune the controller parameters and their results have been compared. To make the analysis much more relevant to practical systems, diff erent load perturbations are also considered i.e. low, medium, and heavy load perturbation. Results obtained demonstrate the effi ciency of the proposed approach with SSA giving the best tuned parameters for the controllers studied

Anti-Proliferative Activities of Vasicinone on Lung Carcinoma Cells Mediated via Activation of Both Mitochondria-Dependent and Independent Pathways

Dey, Tapan,Dutta, Prachurjya,Manna, Prasenjit,Kalita, Jatin,Boruah, Hari Prasanna Deka,Buragohain, Alak Kumar,Unni, Balagopalan The Korean Society of Applied Pharmacology 2018 Biomolecules & Therapeutics(구 응용약물학회지) Vol.26 No.4

Vasicinone, a quinazoline alkaloid from Adhatoda vasica Nees. is well known for its bronchodilator activity. However its anti-proliferative activities is yet to be elucidated. Here-in we investigated the anti-proliferative effect of vasicinone and its underlying mechanism against A549 lung carcinoma cells. The A549 cells upon treatment with various doses of vasicinone (10, 30, 50, $70{\mu}M$) for 72 h showed significant decrease in cell viability. Vasicinone treatment also showed DNA fragmentation, LDH leakage, and disruption of mitochondrial potential, and lower wound healing ability in A549 cells. The Annexin V/PI staining showed disrupted plasma membrane integrity and permeability of PI in treated cells. Moreover vasicinone treatment also lead to down regulation of Bcl-2, Fas death receptor and up regulation of PARP, BAD and cytochrome c, suggesting the anti-proliferative nature of vasicinone which mediated apoptosis through both Fas death receptors as well as Bcl-2 regulated signaling. Furthermore, our preliminary studies with vasicinone treatment also showed to lower the ROS levels in A549 cells and have potential free radical scavenging (DPPH, Hydroxyl) activity and ferric reducing power in cell free systems. Thus combining all, vasicinone may be used to develop a new therapeutic agent against oxidative stress induced lung cancer.

Identification and Characterization of a Novel Antibacterial Peptide, Avian β-Defensin 2 from Ducks

Deying Ma,Ruiqin Wang,Wenyan Liao,Zongxi Han,Shengwang Liu 한국미생물학회 2009 The journal of microbiology Vol.47 No.5

In this study, a novel avian β-defensin (AvBD) was isolated from duck pancreas. The complete nucleotide sequence of the gene contained an 195 bp open reading frame encoding 64 amino acids. Homology, characterization and comparison of the gene with AvBD from other avian species confirmed that it was duck AvBD2. The mRNA expression of the gene was analyzed in 17 tissues from 21-day-old ducks. AvBD2 was highly expressed in the trachea, crop, heart, bone marrow, and pancreas; moderately expressed in the muscular stomach, small intestine, kidney, spleen, thymus, and bursa of Fabricius; and weakly expressed in skin. We produced and purified recombinant AvBD2 by expressing the gene in Escherichia coli. As expected, the recombinant peptide exhibited strong bactericidal properties against Bacillus cereus, Staphylococcus aureus, and Pasteurella multocida, and weak bactericidal properties against E. coli and Salmonella choleraesuis. In addition, the recombinant protein retained antimicrobial activity against S. aureus under different temperatures (range, -20°C to 100°C) and pH values (range, 3 to 12).

Kinetics and Mechanism of the Aminolysis of Dimethyl Thiophosphinic Chloride with Anilines

Dey, Nilay Kumar,Kim, Chan-Kyung,Lee, Hai-Whang Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.4