Investigations of H-Darrieus rotors for different blade parameters at low wind speeds

Sengupta, Anal R.,Biswas, Agnimitra,Gupta, Rajat Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.25 No.6

Studies of unsymmetrical blade H-Darrieus rotors at low wind speeds in terms of starting time, static torque, and power performances for different blade parameters: thickness-to-chord (t/c), camber position, and solidity are scarce. However these are required for knowing insights of rotor performances to obtain some design guidelines for the selection of these rotors. Here, an attempt is made to quantify the effects of these blade parameters on the performances of three different H-Darrieus rotors at various low wind streams. Different blade profiles, namely S815, EN0005 (both unsymmetrical), and NACA 0018 (symmetrical blade for comparison) are considered. The rotors are investigated rigorously in a centrifugal blower apparatus. Firstly the dynamic and static performances of the rotors are evaluated to determine the best performing rotor and their optimum solidity. Generalised performance equations are developed based on selected blade parameters which are validated for the unsymmetrical rotors. Further, the starting time is quantified with respect to the rotor inertia to determine the suitable range of inertia that helps the unsymmetrical blade rotor to self-start earlier than the symmetrical one. This study can work as a benchmark for the selection of optimum blade parameters while designing an unsymmetrical blade rotor at low wind speeds.

H I in the Arp 202 system and its tidal dwarf candidate

Sengupta, C.,Scott, T. C.,Dwarakanath, K. S.,Saikia, D. J.,Sohn, B. W. Oxford University Press 2014 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.444 No.1

SAMPLING BASED UNCERTAINTY ANALYSIS OF 10 % HOT LEG BREAK LOCA IN LARGE SCALE TEST FACILITY

Sengupta, Samiran,Dubey, S.K.,Rao, R.S.,Gupta, S.K.,Raina, V.K Korean Nuclear Society 2010 Nuclear Engineering and Technology Vol.42 No.6

Sampling based uncertainty analysis was carried out to quantify uncertainty in predictions of best estimate code RELAP5/MOD3.2 for a thermal hydraulic test (10% hot leg break LOCA) performed in the Large Scale Test Facility (LSTF) as a part of an IAEA coordinated research project. The nodalisation of the test facility was qualified for both steady state and transient level by systematically applying the procedures led by uncertainty methodology based on accuracy extrapolation (UMAE); uncertainty analysis was carried out using the Latin hypercube sampling (LHS) method to evaluate uncertainty for ten input parameters. Sixteen output parameters were selected for uncertainty evaluation and uncertainty band between $5^{th}$ and $95^{th}$ percentile of the output parameters were evaluated. It was observed that the uncertainty band for the primary pressure during two phase blowdown is larger than that of the remaining period. Similarly, a larger uncertainty band is observed relating to accumulator injection flow during reflood phase. Importance analysis was also carried out and standard rank regression coefficients were computed to quantify the effect of each individual input parameter on output parameters. It was observed that the break discharge coefficient is the most important uncertain parameter relating to the prediction of all the primary side parameters and that the steam generator (SG) relief pressure setting is the most important parameter in predicting the SG secondary pressure.

Highly stereoselective synthesis of mupirocin H

Sengupta, S.,Kim, H.J.,Cho, K.S.,Song, W.Y.,Sim, T. Pergamon Press 2017 Tetrahedron Vol.73 No.8

A highly diastereoselective and efficient convergent synthesis of mupirocin H starting from (+)-®-Roche ester was achieved. Grubbs cross metathesis was employed as the key step in the pathway to generate an important E-olefin intermediate. Other processes utilized in the route include a Pd-catalysed stereoselective substitution reaction of a cis epoxide, Sharpless epoxidation followed by Red-Al promoted epoxide ring opening, and Seebach methylation and a TEMPO/BAIB mediated oxidation-lactonization sequence. Finally, we observed that mupirocin H inhibits SbnE, a synthetase required for staphyloferrin B biosynthesis.

One-dimensional itinerant ferromagnets with Heisenberg symmetry and the ferromagnetic quantum critical point

Sengupta, K.,Kim, Yong Baek American Physical Society 2005 Physical review. B, Condensed matter and materials Vol.71 No.17

Identification and determination of the number of immature green citrus fruit in a canopy under different ambient light conditions

Sengupta, S.,Lee, W.S. Academic Press 2014 BIOSYSTEMS ENGINEERING Vol.117 No.-

Yield mapping for tree crops by mechanical harvesting requires automatic detection and counting of fruits in tree canopy. However, partial occlusion, shape irregularity, varying illumination, multiple sizes and similarity with the background make fruit identification a very difficult task to achieve. Therefore, immature green citrus-fruit detection within a green canopy is a challenging task due to all the above-mentioned problems. A novel algorithmic technique was used to detect immature green citrus fruit in tree canopy under natural outdoor conditions. Shape analysis and texture classification were two integral parts of the algorithm. Shape analysis was conducted to detect as many fruits as possible. Texture classification by a support vector machine (SVM), Canny edge detection combined with a graph-based connected component algorithm and Hough line detection, were used to remove false positives. Next, keypoints were detected using a scale invariant feature transform (SIFT) algorithm and to further remove false positives. A majority voting scheme was implemented to make the algorithm more robust. The algorithm was able to accurately detect and count 80.4% of citrus fruit in a validation set of images acquired from a citrus grove under natural outdoor conditions. The algorithm could be further improved to provide growers early yield estimation so that growers can manage grove more efficiently on a site-specific basis to increase yield and profit.

Arp 65 interaction debris: massive H I displacement and star formation

Sengupta, C.,Scott, T. C.,Paudel, S.,Saikia, D. J.,Dwarakanath, K. S.,Sohn, B. W. EDP Sciences 2015 Astronomy and astrophysics Vol.584 No.-

<P>Context. Pre?merger tidal interactions between pairs of galaxies are known to induce significant changes in the morphologies and kinematics of the stellar and interstellar medium components. Large amounts of gas and stars are often found to be disturbed or displaced as tidal debris. This debris then evolves, sometimes forming stars and occasionally forming tidal dwarf galaxies. Here we present results from our HI study of Arp 65, an interacting pair hosting extended HI tidal debris. Aims. In an effort to understand the evolution of tidal debris produced by interacting pairs of galaxies, including in situ star and tidal dwarf galaxy formation, we are mapping HI in a sample of interacting galaxy pairs. The Arp 65 pair is the latest member of this sample to be mapped. Methods. Our resolved HI 21 cm line survey is being carried out using the Giant Metrewave Radio Telescope. We used our HI survey data as well as available SDSS optical, Spitzer infra-red and GALEX UV data to study the evolution of the tidal debris and the correlation of HI with the star-forming regions within it. Results. In Arp 65 we see a high impact pre?merger tidal interaction involving a pair of massive galaxies (NGC90 and NGC93) that have a stellar mass ratio of ~1:3. The interaction, which probably occurred ~1.0–2.5 × 10<SUP>8</SUP> yr ago, appears to have displaced a large fraction of the HI in NGC90 (including the highest column density HI) beyond its optical disk. We also find extended on-going star formation in the outer disk of NGC90. In the major star-forming regions, we find the HI column densities to be ~4.7 × 10<SUP>20</SUP> cm<SUP>−2</SUP> or lower. But no signature of star formation was found in the highest column density HI debris SE of NGC90. This indicates conditions within the highest density HI debris remain hostile to star formation and it reaffirms that high HI column densities may be a necessary but not sufficient criterion for star formation.</P>

Empirical Tests of New Growth Theory : Openness and Growth

Sengupta, Jati K. 세종대학교 국제경제연구소 1994 Journal of Economic Integration Vol.9 No.3

New growth theory has stressed the role of export externality and increasing returns to scale in promoting sustained growth. This paper discusses these sources of economic growth in Asian NICs(newly industrializing countries) in recent times by applying some modern econometric tests based on cointegration and other methods. Countries such as Japan, Korea and Taiwan are considered as examples for empirical applications of the broad tenets of the new growth theory.

A Concise Synthesis of Mupirocin H Using a Cross‐Metathesis‐Based Strategy

Sengupta, Sandip,Sim, Taebo WILEY‐VCH Verlag 2014 EUROPEAN JOURNAL OF ORGANIC CHEMISTRY Vol.2014 No.23

<P><B>Abstract</B></P><P>A highly efficient (10.1 % overall yield) and convergent (longest linear sequence of 16 steps) synthesis of mupirocin H has been achieved, starting from commercially available (+)‐(<I>R</I>)‐Roche ester. The route relies on an efficient Grubbs cross‐metathesis reaction to generate a key, late‐stage <I>E</I>‐olefin intermediate, and a cobalt‐catalysed diastereoselective Reformatsky reaction to produce a β‐hydroxy ester that serves as a late‐stage intermediate.</P>

A Novel Draft Genome-Scale Reconstruction Model of Isochrysis sp: Exploring Metabolic Pathways for Sustainable Aquaculture Innovations

Sengupta Abhishek,Gupta Tushar,Chakraborty Aman,Kulshrestha Sudeepti,Redhu Ritu,Bhattacharjya Raya,Tiwari Archana,Narad Priyanka 한국미생물·생명공학회 2024 한국미생물·생명공학회지 Vol.52 No.2

Isochrysis sp. is a sea microalga that has become a species of interest because of the extreme lipid content and rapid growth rate of this organism indicating its potential for efficient biofuel production. Using genome sequencing/genome-scale modeling for the prediction of Isochrysis sp. metabolic utilities there is high scope for the identification of essential pathways for the extraction of byproducts of interest at a higher rate. In our work, we design and present iIsochr964, a genome-scale metabolic model of Isochrysis sp. including 4315 reactions, 934 genes, and 1879 metabolites, which are distributed among fourteen compartments. For model validation, experimental culture, and isolation of Isochrysis sp. were performed and biomass values were used for validation of the genome-scale model. OptFlux was instrumental in uncovering several novel metabolites that influence the organism's metabolism by increasing the flux of interacting metabolites, such as Malonyl-CoA, EPA, Protein and others. iIsochr964 provides a compelling resource of metabolic understanding to revolutionize its industrial applications, thereby fostering sustainable development and allowing estimations and simulations of the organism metabolism under varying physiological, chemical, and genetic conditions. It is also useful in principle to provide a systemic view of Isochrysis sp. metabolism, efficiently guiding research and granting context to omics data.