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.

Extraction of Exact Layer Thickness of Ultra-thin Gate Dielectrics in Nanoscaled CMOS under Strong Inversion

Dey, Munmun,Chattopadhyay, Sanatan The Institute of Electronics and Information Engin 2010 Journal of semiconductor technology and science Vol.10 No.2

The impact of surface quantization on device parameters of a Si metal oxide semiconductor (MOS) capacitor has been analyzed in the present work. Variation of conduction band bending, position of discrete energy states, variation of surface potential, and the variation of inversion carrier concentration at charge centroid have been analyzed for different gate voltages, substrate doping concentrations and oxide thicknesses. Oxide thickness calculated from the experimental C-V data of a MOS capacitor is different from the actual oxide thickness, since such data include the effect of surface quantization. A correction factor has been developed considering the effect of charge centroid in presence of surface quantization at strong inversion and it has been observed that the correction due to surface quantization is crucial for highly doped substrate with thinner gate oxide.

Kinetics and Mechanism of the Pyridinolyses of Dimethyl Phosphinic and Thiophosphinic Chlorides in Acetonitrile

Dey, Nilay Kumar,Adhikary, Keshab Kumar,Kim, Chan-Kyung,Lee, Hai-Whang Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.12

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

Weed Control by Herbicides and Fertilizers Applied Separately or Combined on Kentucky Bluegrass Lawn

Deying Li(다이엥 리),Kirk Howatt(컬크 호와트) 한국잡초학회·한국잔디학회 2007 Weed & Turfgrass Science Vol.21 No.1

잔디밭 관리 시 제초제와 비료의 혼합 처리는 시간절약 및 답압감소 등 여러 가지 장점이 있다. Weed & Feed는 제초제와 비료를 혼합 조제된 제품이다. 본 실험은 캔터키 블루그래스 잔디밭에서 비료 및 제초제를 단독으로 처리할 때와 Weed & Feed를 사용할 경우 그 효과를 비교하기 위해서 시작되었다. 실험에 사용한 Weed & Feed 28-3-3에는 세 가지 제초제 - 2,4-D 0.64%, MCPP 0.31% 및 dicamba 0.03%가 혼합 조제된 약제이다. 첫 번째 처리는 5월에 실시하였고, 두 번째 처리는 6월 또는 9월에 실시하였다. 단독으로 사용한 제초제는 2,4-D(LV-4, 4EC), MCPP(4EC) 및 dicamba(Clarity, 4EC)로 Weed & Feed의 50% 및 100% 수준으로 적용하였다. 실험기간 동안 우점 잡초는 민들레였으며, 제2 우점종은 2004년에는 엉컹키, 2005년에는 왕질경이로 나타났다. 실험결과 5월과 6월에 비료와 100% 수준의 제초제를 처리할 경우 수용할 수 있는 잔디밭 품질은 각각 112.3일과 83.7일 정도 유지되엇다. 하지만 Weed & Feed를 사용할 경우에는 각각 58.7일과 83.7일로 나타났다. Weed & Feed 효과는 사용 시기에 따라 차이는 있지만 비료와 50% 수준의 제초제를 처리한 것과 유사한 효과가 있는 것으로 나타났다. 잡초 방제 시 Weed & Feed에 비해 비료와 100% 수준의 제초제를 직접 처리하는 것은 Weed & Feed를 사용하는 그 이상의 효과가 있는 것으로 나타났다. Incorporating herbicides application into fertilization has several benefits including saving time and reducing traffics on the lawn. Premixed products of fertilizers and herbicides are commonly known as Weed & Feed in the lawn-care industry. To compare Weed & Feed with separate applications of fertilizers and herbicides on a Kentucky bluegrass (Poa pratensis L.) lawn, a Weed & Feed 28-3-3, containing 0.64% 2,4-D, 0.31% MCPP, and 0.03% dicamba of active ingredients, was used in this study. The first application was in May, with the second in June or Sept. Herbicides in forms of 2,4-D (LV-4, 4EC), MCPP (4EC), and dicamba (Clarity, 4EC) were applied at rates equal to the amounts in Weed & Feed or at half of the rates. The dominant weed in both locations was common dandelion (Taraxacum officinale Weber.) in 2005 and 2004. A secondary weed was Canada thistle (Cirsium arvense (L.) Scop.) in 2004 and broadleaf plantain (Plantago major L.) in 2005. When applied in May and June, fertilizer plus full rate of herbicides treatment achieved 112.3 and 83.7 days of acceptable turf quality in 2004 and 2005, respectively. During the same period, Weed & Feed resulted in 58.7 and 24.3 days of acceptable turf quality, respectively. Our study showed that Weed & Feed was generally as effective in weed control as the same amount of fertilizer plus half rates of herbicides sprayed although results may vary due to the timing of application. Fertilizer plus full rates of herbicides provided the same or better results of weed control than Weed & Feed.

Hilbert series for moduli spaces of instantons on ℂ2/ℤ n

Dey, Anindya,Hanany, Amihay,Mekareeya, Noppadol,Rodrí,guez-Gó,mez, Diego,Seong, Rak-Kyeong Springer-Verlag 2014 Journal of high energy physics Vol.2014 No.1

Anilinolysis of Diphenyl Thiophosphinic Chloride and Theoretical Studies on Various R₁R₂P(O or S)Cl

Dey, Nilay Kumar,Han, In-Suk,Lee, Hai-Whang Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.11

The aminolysis of diphenyl thiophosphinic chloride (2) with substituted anilines in acetonitrile at 55.0 oC is investigated kinetically. Kinetic results yield large Hammett ρX (ρnuc = ?3.97) and Bronsted βX (βnuc = 1.40) values. A concerted mechanism involving a partial frontside nucleophilic attack through a hydrogen-bonded, four-center type transition state is proposed on the basis of the primary normal kinetic isotope effects (kH/kD = 1.0-1.1) with deuterated aniline (XC6H4ND2) nucleophiles. The natural bond order charges on P and the degrees of distortion of 42 compounds: chlorophosphates [(R1O)(R2O)P(=O)Cl], chlorothiophosphates [(R1O)(R2O)P(=S)Cl], phosphonochloridates [(R1O)R2P(=O)Cl], phosphonochlorothioates [(R1O)R2P(=S)Cl], chlorophosphinates [R1R2P(=O)Cl], and chlorothiophosphinates [R1R2P(=S)Cl] are calculated at the B3LYP/ 6-311+G(d,p) level in the gas phase.