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.

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

SAMIRAN SENGUPTA,S. K. DUBEY,R. S. RAO,S. K. GUPTA,V. K RAINA 한국원자력학회 2010 Nuclear Engineering and Technology Vol.42 No.6

Sampling based uncertainty analysis was carried out to quantify uncertainty in predictions of best estimate codeRELAP5/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 andtransient 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 forten input parameters. Sixteen output parameters were selected for uncertainty evaluation and uncertainty band between 5thand 95thpercentile of the output parameters were evaluated. It was observed that the uncertainty band for the primary pressure duringtwo phase blowdown is larger than that of the remaining period. Similarly, a larger uncertainty band is observed relating toaccumulator injection flow during reflood phase. Importance analysis was also carried out and standard rank regression coefficientswere computed to quantify the effect of each individual input parameter on output parameters. It was observed that the breakdischarge coefficient is the most important uncertain parameter relating to the prediction of all the primary side parametersand that the steam generator (SG) relief pressure setting is the most important parameter in predicting the SG secondary pressure.

Subfertility in Males: An Important Cause of Bull Disposal in Bovines

Mukhopadhyay, C.S.,Gupta, A.K.,Yadav, B.R.,Khate, K.,Raina, V.S.,Mohanty, T.K.,Dubey, P.P. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.4

The study had two objectives, namely, to estimate the andrological disorders leading to disposal of Karan Fries (KF), Sahiwal cattle and Murrah buffalo bulls and to study the effect of various factors (species/breeds, season of birth and period of birth) on male reproductive parameters. Records on occurrence of subfertility problems and disposal pattern of bulls maintained at the National Dairy Research Institute herd were collected for 15 years (1991 to 2005). Percentage of bulls producing freezable semen was less in the crossbred cattle (58.46%) as compared to Sahiwal (81.69%) and Murrah bulls (81.05%). Various subfertility traits like poor libido and unacceptable seminal profile were found to be the significant reasons (p<0.01) for culling of the breeding bulls. Inadequate sex drive was the main contributing factor for bull disposal in Sahiwal (22.55%) and Murrah bulls (15.12%) whereas poor semen quality and freezability were most frequently observed in KF bulls (24.29 and 7.29 percent, respectively). Least squares analyses of different male reproductive parameters showed that species/breeds had significant effect (p<0.05) on all traits except for frozen semen production periods (FSPP). Periods of birth were significantly different (p<0.05) for all traits except for semen volume. Age at first semen collection (AFSC), age at first semen freezing (AFSF) and age at disposal (AD) were highest in Murrah, while frozen semen production period (FSPP) and semen production period (SPP) were highest in KF and lowest in Sahiwal. The age at first semen donation and breeding period could be reduced by introducing the bulls to training at an early age. These results revealed a declining trend in AFSC, AFSF, FSPP, SPP and AD, thereby indicating an improvement in reproductive performance over the years. The age at first semen donation in bovines can be reduced by introducing the young male calves to training at an early age, which could increase the dosage of semen obtained from each male.

Optical-chemical-microphysical relationships and closure studies for mixed carbonaceous aerosols observed at Jeju Island; 3-laser photoacoustic spectrometer, particle sizing, and filter analysis

Flowers, B. A.,Dubey, M. K.,Mazzoleni, C.,Stone, E. A.,Schauer, J. J.,Kim, S.-W.,Yoon, S. C. Copernicus GmbH 2010 Atmospheric Chemistry and Physics Vol.10 No.21

<P>Abstract. Transport of aerosols in pollution plumes from the mainland Asian continent was observed in situ at Jeju, South Korea during the Cheju Asian Brown Cloud Plume-Asian Monsoon Experiment (CAPMEX) field campaign throughout August and September 2008 using a 3-laser photoacoustic spectrometer (PASS-3), chemical filter analysis, and size distributions. The PASS-3 directly measures the effects of morphology (e.g. coatings) on light absorption that traditional filter-based instruments are unable to address. Transport of mixed sulfate, carbonaceous, and nitrate aerosols from various Asian pollution plumes to Jeju accounted for 74% of the deployment days, showing large variations in their measured chemical and optical properties. Analysis of eight distinct episodes, spanning wide ranges of chemical composition, optical properties, and source regions, reveals that episodes with higher organic carbon (OC)/sulfate (SO42−) and nitrate (NO3−)/SO42− composition ratios exhibit lower single scatter albedo at shorter wavelengths (ω405). We infer complex refractive indices (n-ik) as a function of wavelength for the high, intermediate, and low OC/SO42− pollution episodes by using the observed particle size distributions and the measured optical properties. The smallest mean particle diameter corresponds to the high OC/SO42− aerosol episode. The imaginary part of the refractive index (k) is greater for the high OC/SO42− episode at all wavelengths. A distinct, sharp increase in k at short wavelength implies enhanced light absorption by OC, which accounts for 50% of the light absorption at 405 nm, in the high OC/SO42− episode. Idealized analysis indicates increased absorption at 781 nm by factors greater than 3 relative to denuded black carbon in the laboratory. We hypothesize that coatings of black carbon cores are the mechanism of this enhancement. This implies that climate warming and atmospheric heating rates from black carbon particles can be significantly larger than have been estimated previously. The results of this study demonstrate ways in which atmospheric processing and mixing can amplify particle light absorption for carbonaceous aerosol, significantly at short wavelength, underscoring the need to understand and predict chemical composition effects on optical properties to accurately estimate the climate radiative forcing by mixed carbonaceous aerosols. </P>

Enhanced photoluminescence response of Ca²⁺/Ba²⁺ substituted solid solutions of SrS:Ce phosphors

Vij, Ankush,Kumar, Shalendra,Won, S.O.,Chae, K.H.,Dubey, Abhinav,Kumar, Ravi Elsevier 2018 Materials letters Vol.227 No.-

<P><B>Abstract</B></P> <P>The quest of improving luminescence efficiency in alkaline earth sulfide phosphors has been of great interest due to their applications in diverse areas. We synthesized SrS:Ce<SUB>0.05</SUB>, Sr<SUB>0.75</SUB>Ba<SUB>0.20</SUB>S:Ce<SUB>0.05</SUB>, Sr<SUB>0.75</SUB>Ca<SUB>0.20</SUB>S:Ce<SUB>0.05</SUB> and Sr<SUB>0.75</SUB>Ca<SUB>0.10</SUB>Ba<SUB>0.10</SUB>S:Ce<SUB>0.05</SUB> phosphors using solid state diffusion method. X-ray diffraction patterns of all the samples were found similar to the cubic SrS phase except minor shifts in angles. To ascertain the valence state of Ce, near edge X-ray absorption fine structure spectroscopy was employed using synchrotron radiations. We simulated Ce M<SUB>5,4</SUB>-edges of Ce<SUP>3+</SUP> ions using atomic multiplet calculations, which agrees well with the experimental data, clearly suggesting that Ce enters as Ce<SUP>3+</SUP> in all the samples. The photoluminescence spectra of synthesized phosphors exhibit blue-green emission assigned to the 5d-4f transitions in Ce<SUP>3+</SUP> levels, with minor shifts in wavelength. Interestingly, Ca<SUP>2+</SUP>/Ba<SUP>2+</SUP>substitution in SrS:Ce phosphors increases the PL intensity considerably. In comparison to SrS:Ce<SUB>0.05</SUB> , PL intensity of Sr<SUB>0.75</SUB>Ca<SUB>0.10</SUB>Ba<SUB>0.10</SUB>S:Ce<SUB>0.05</SUB> phosphors was enhanced by 2.7 times, which may be exploited in many optical applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Probed the effect of Ca<SUP>2+</SUP>/Ba<SUP>2+</SUP> substituted solid solutions of SrS:Ce<SUB>0.05</SUB> phosphors. </LI> <LI> NEXAFS spectra collected at Ce-M<SUB>5,4</SUB> edges confirms presence of Ce<SUP>3+</SUP>. </LI> <LI> PL intensity increases appreciably with Ca<SUP>2+</SUP>/Ba<SUP>2+</SUP> substitution in SrS:Ce. </LI> <LI> SrCaBaS:Ce exhibits maximum PL efficiency, 2.7 times as that of SrS:Ce phosphors. </LI> <LI> Enhanced PL emission in SrCaBaS:Ce can be exploited in many optical applications. </LI> </UL> </P>

Trachyspermum ammi (L.) fruit essential oil influencing on membrane permeability and surface characteristics in inhibiting food-borne pathogens

Paul, S.,Dubey, R.C.,Maheswari, D.K.,Kang, S.C. Butterworths ; Taylor Francis ; Elsevier Science 2011 Food control Vol.22 No.5

This study was aimed to evaluate the anti-bacterial potential of the essential oil and extracts of Trachyspermum ammi fruits against food borne and spoilage bacteria. The chemical compositions of the oil were analyzed by GC-MS. Thirty compounds representing 91.39% of the total oil were identified. The extracellular ATP concentration, release of cell constituents and potassium ions from the bacterial cell were measured after treatment with essential oil of T. ammi at MIC concentration. The oil, and extracts of hexane, chloroform, ethyl acetate and methanol of T. ammi fruits displayed remarkable anti-bacterial effects against Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa KCTC 2004, Salmonella typhimurium KCTC 2515, Enterobactor aerogens KCTC 2190 and Staphylococcus aureus ATCC 6538. The scanning electron microscopic studies also demonstrated inhibitory effect of the oil on the morphology of B. subtilis ATCC 6633 at the MIC concentration, along with the potential effect on cell viabilities of the tested bacteria.

Effect of Precipitate Characteristics on the Corrosion Behavior of a AZ80 Magnesium Alloy

Dhananjay Dubey,Kondababu Kadali,Harikrishna Kancharla,Anuz Zindal,Jayant Jain,K. Mondal,Sudhanshu S. Singh 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

In this study, a systematic investigation on the effect of both aging temperature (250 °C and 330 °C) and time (chosen basedon aging curves) on the distribution and volume fraction of the Mg17Al12precipitates and subsequently on the corrosionbehavior of the AZ80 magnesium alloy was carried out by conducting both immersion and dynamic polarization test in afreely aerated 3.5% NaCl solution. The analysis of corrosion products using Raman spectroscopy and X-ray diffraction andinvestigation of corrosion morphologies using scanning electron microscopy suggested galvanic corrosion of the anodicα-Mg matrix in contact with the cathodic Mg17Al12precipitates. The higher corrosion resistance of the alloy aged at lowertemperature (250 °C) was attributed to the higher number density of the Mg17Al12precipitates than that at higher temperature(330 °C). In the peak aged condition, the average number densities of precipitates (1/μm2) were measured to be ~ 0.74and ~ 0.32 and average corrosion rates (mm/y) were measured to be ~ 3.0 and ~ 5.0 at the aging temperatures of 250 °Cand 330 °C, respectively. At a particular aging temperature, the corrosion resistance increased to a maximum at peak-agedcondition followed by a decline in the over-aged condition and further increase with prolong aging, which was correlatedwith the number density, size and distribution of the Mg17Al12precipitates.

Equations to evaluate fundamental period of vibration of buildings in seismic analysis

Sangamnerkar, Prakash,Dubey, S.K. Techno-Press 2017 Structural monitoring and maintenance Vol.4 No.4

In this study effects of various parameters like a number of bays, the stiffness of the structure along with the height of the structure was examined. The fundamental period of vibration T of the building is an important parameter for evaluation of seismic base shear. Empirical equations which are given in the Indian seismic code for the calculation of the fundamental period of a framed structure, primarily as a function of height, and do not consider the effect of number of bays and stiffness of the structure. Building periods predicted by these expressions are widely used in practice, although it has been observed that there is scope for further improvement in these equations since the height alone is inadequate to explain the period variability. The aim of this study is to find the effects of a number of bays in both the directions, the stiffness of the structure and propose a new period equation which incorporates a number of bays, plan area, stiffness along with the height of the structure.

Green emission from Tb³⁺-doped CaLaAl₃O₇ phosphor – A photoluminescence study

Singh, Vijay,Shinde, K.N.,Pathak, M.S.,Singh, N.,Dubey, Vikas,Singh, Pramod K.,Jirimali, H.D. Elsevier 2018 OPTIK -STUTTGART- Vol.164 No.-

<P><B>Abstract</B></P> <P>A series of Tb<SUP>3+</SUP>-doped CaLaAl<SUB>3</SUB>O<SUB>7</SUB> phosphors were successfully synthesized via a sol-gel method. The formation of the synthesized phosphors was confirmed using X-ray powder diffraction (XRPD) studies. A scanning electron microscope (SEM) was used to characterize the surface morphology and to investigate the photoluminescence behaviors in detail. Under the excitation of 235 nm, the emission spectrum consists of the characteristic Tb<SUP>3+</SUP> transitions that mainly peak at 543 nm and correspond to the <SUP>5</SUP>D<SUB>4</SUB> → <SUP>7</SUP>F<SUB>5</SUB> transition. The intensity was greatly improved due to the Tb<SUP>3+</SUP> concentration in the present phosphors. The optimum Tb<SUP>3+</SUP>-doping concentration was determined to be 0.05 mol. The chromaticity coordinates of the CaLaAl<SUB>3</SUB>O<SUB>7</SUB>:Tb<SUP>3+</SUP> were fixed to make it tunable for the blue-to-green region. The typical photographs of the CaLaAl<SUB>3</SUB>O<SUB>7</SUB>:Tb<SUP>3+</SUP> under a 254-nm UV light revealed an intense-green powder. The results showed that this kind of phosphor is potentially applicable in terms of UV-excited white LEDs.</P>

Green emitting Tb doped LiBaB₉O₁₅ phosphors

Singh, Vijay,Shinde, K.N.,Singh, N.,Pathak, M.S.,Singh, Pramod K.,Dubey, Vikas Elsevier 2018 OPTIK -STUTTGART- Vol.156 No.-

<P><B>Abstract</B></P> <P>A successful preparation of a Tb<SUP>3+</SUP>-doped LiBaB<SUB>9</SUB>O<SUB>15</SUB> phosphors was achieved through the use of a solution-combustion method. The preparation of the powders of the Tb<SUP>3+</SUP>-doped LiBaB<SUB>9</SUB>O<SUB>15</SUB> phosphor was confirmed by X-ray diffraction (XRD) results; furthermore, the size and morphology of these powders were further examined using a scanning electron microscope (SEM). A study of the luminescent proprieties under a UV excitation showed a dominant and strong green luminescent peak at 542nm that is due to the d–f transition. When monitored at 542nm, the excitation spectrum exhibited a broad band centered at 230nm and several weak peaks in the wavelength range of 300–400nm that are attributed to the f-d transitions and the intra-4f-4f transitions of the Tb<SUP>3+</SUP> ions, respectively. The addition of the Tb<SUP>3+</SUP> concentration greatly improved the photoluminescent properties of the present phosphors, and the Commission International de I’Eclairage (CIE) chromaticity coordinates are located in the green region. The present study suggests that the potential applications of the Tb<SUP>3+</SUP>-doped LiBaB<SUB>9</SUB>O<SUB>15</SUB> phosphors might be in the lighting and display fields.</P>