Performance evaluation and reliability analysis of a complex system with three possibilities in repair with the application of copula

B. Nailwal,S. B. Singh 한국신뢰성학회 2011 International Journal of Reliability and Applicati Vol.12 No.1

This paper deals with the reliability analysis of a complex system with three possibilities at the time of repair. The considered system consists of two subsystems A and Bin series configuration (1-out-of-2: F). Subsystem A has n units which are connected in series whereas subsystem B consists of n units in parallel configuration. The configuration of subsystem A is of 1-out-of-n: F whereas subsystem B is of k-out-of-n: D and k+1-out-of-n: F nature. System has three states: Good, degraded and failed. Supplementary variable technique has been used for mathematical formulation of the model. Laplace transform is being utilized to solve the mathematical equation. Reliability, Availability, M.T.T.F., Busy Period and Cost effectiveness of the system have been computed. The repairs from state S7 to S0, S8 to S0, S9 to S0 and S11 to S0 have two types namely exponential and general. Joint probability distribution of repair rate from S7 to S0, S8 to S0, S9 to S0 and S11 to S0 is computed by Gumbel-Hougaard family of copula. Some particular cases of the system have also been derived to see the practical importance of the model.

Site-specific mutagenesis of yeast 2-Cys peroxiredoxin improves heat or oxidative stress tolerance by enhancing its chaperone or peroxidase function

Hong, S. H.,Lee, S. S.,Chung, J. M.,Jung, H. s.,Singh, S.,Mondal, S.,Jang, H. H.,Cho, J. Y.,Bae, H. J.,Chung, B. Y. Springer Science + Business Media 2017 Protoplasma Vol.254 No.1

<P>Yeast peroxiredoxin II (yPrxII) is an antioxidant enzyme that plays a protective role against the damage caused by reactive oxygen species (ROS) in Saccharomyces cerevisiae. This enzyme consists of 196 amino acids containing 2-Cys Prx with highly conserved two active cysteine residues at positions 48 and 171. The yPrxII has dual enzymatic functions as a peroxidase and molecular chaperone. To understand the effect of additional cysteine residues on dual functions of yPrxII, S79C-yPrxII and S109C-yPrxII, the substitution of Ser with Cys residue at 79 and 109 positions, respectively, was generated. S109C-yPrxII and S79C-yPrxII showed 3.7- and 2.7-fold higher chaperone and peroxidase activity, respectively, than the wild type (WT). The improvement in enzyme activity was found to be closely associated with structural changes in proteins. S109C-yPrxII had increased beta-sheet in its secondary structure and formed high-molecular-weight (HMW) as well as low-molecular-weight (LMW) complexes, but S79C-yPrxII formed only LMW complexes. HMW complexes predominantly exhibited a chaperone function, and LMW complexes showed a peroxidase function. In addition, transgenic yeast cells over-expressing Cys-substituted yPrxII showed greater tolerance against heat and oxidative stress compared to WT-yPrxII.</P>

EPR and optical investigation of ultraviolet-emitting Gd3Ga5O12 garnet

Singh, Vijay,Sivaramaiah, G.,Singh, N.,Mohapatra, M.,Hakeem, D. A.,Pathak, M. S.,Rao, J. L. Springer-Verlag 2018 Journal of materials science Materials in electron Vol.29 No.2

<P>Gd3Ga5O12 garnet was prepared by a solution combustion method and characterized using powder X-ray diffraction, electron paramagnetic resonance (EPR) and optical spectroscopic techniques. EPR spectrum of the samples at ambient and low temperatures exhibited resonance signal at g approximate to 2 attributed to Gd3+ ions disposed in an octahedral symmetry. The optical absorption spectrum showed a band centered at 274 nm attributed to S-8(7/2)-> I-6(J) transition of the Gd3+ ions. The excitation spectrum showed a maximum at 273 nm along with two relatively weaker peaks at 276 and 279 nm. These three excitation bands were assigned to the transitions S-8(7/2)-> I-6(J). The emission spectrum showed two peaks centered at 311 and 306 nm that were assigned to the transitions P-6(7/2)-> S-8(7/2) and P-6(5/2)-> S-8(7/2) of Gd3+, respectively. To evaluate the phosphor performance, several magnetic and thermodynamic parameters for the system were calculated adopting standard procedure.</P>

Combustion Synthesized Europium Doped LaAl₁₁O₁₈ Phosphors—An Electron Paramagnetic Resonance and Optical Study

Singh, Vijay,Sivaramaiah, G.,Rao, J. L.,Kumaran, R. Senthil,Dhoble, S. J. American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.1

<P>By adopting a facile solution combustion synthesis, crystallized europium doped blue phosphors were successfully prepared. These phosphors were characterized by X-ray diffraction (XRD), Fourier transform infrared absorption (FT-IR), energy dispersive analysis of X-ray, Electron Paramagnetic Resonance (EPR) and Photoluminescence (PL) experimental methods. The photoluminescence spectrum indicates Eu2+ and Eu3+ ions in these phosphors. The band at around 442 nm is attributed to the spin-allowed 4f(6)5d(1) (D-2) -> (4)f(7)(S-6(7/2)) transition of Eu2+ ions. The sharp bands at 591 (D-5(0) -> F-7(1)) and 616 (D-5(0) -> F-7(2)) nm are attributed to the spin-forbidden transitions of Eu3+ ions. The EPR spectra of as-prepared and post-treated LaAl11O18:Eu phosphors exhibit signals characteristic of La2+ and Eu2+ ions. The number of spins, Gibbs energy, magnetic susceptibility, Curie constant and effective magnetic moment values were calculated and compared at 296 and 110 K.</P>

Probing the Thermodynamic and Magnetic Properties of UV-B-Emitting GdAlO3 Phosphors by ESR and Optical Techniques

Singh, V.,Sivaramaiah, G.,Mohapatra, M.,Rao, J. L.,Singh, N.,Pathak, M. S.,Singh, P. K.,Dhoble, S. J. Springer Science + Business Media 2017 Journal of Electronic Materials Vol.46 No.2

<P>GdAlO3 phosphor samples have been prepared by a solution combustion method. X-ray diffraction analysis revealed that the GdAlO3 phosphor stabilized in orthorhombic phase. The optical absorption spectrum showed bands due to Gd3+ ions as well as defect level in the host. The excitation spectrum exhibited a dominant band with maximum at 273 nm. Upon excitation at 273 nm, ultraviolet-B (UV-B) emission with maximum at 312 nm was observed from the undoped sample, being attributed to P-6(7/2) -> S-8(7/2) transition of Gd3+ ion. The UV-B emission was enhanced at liquid-nitrogen temperature (77 K), most probably due to increased ground-state population according to the Boltzmann distribution law. Electron spin resonance spectra of samples at both room and liquid-nitrogen temperature exhibited resonance signals at g ae 2, attributed to Gd3+ ions arranged with octahedral symmetry linked via oxygen bridges. Various magnetic and thermodynamic parameters for the phosphor system were evaluated by standard procedures. Correlation of these values with the optical properties suggested that the GdAlO3 phosphor can be effectively used as an UV-B light source for industrial applications at room temperature.</P>

A comparison of native and acid thinned normal and waxy corn starches: Physicochemical, thermal, morphological and pasting properties

Singh Sandhu, K.,Singh, N.,Lim, S.T. Academic Press, etc 2007 FOOD SCIENCE AND TECHNOLOGY -ZURICH- Vol.40 No.9

The starches isolated from normal and waxy corn varieties were hydrolyzed with hydrochloric acid (0.14mol equivalent/L) and evaluated for physicochemical and functional properties. Acid thinning decreased the amylose content and swelling power but increased the solubility. The light transmittance of acid thinned (AT) starch pastes was higher than those of their native starches after similar storage intervals. The scanning electron microscopic observation demonstrated that the acid thinning did not cause any disruption of the granular crystalline structure. Native normal corn starches showed lower onset temperature (T<SUB>o</SUB>) and peak temperature (T<SUB>p</SUB>) as compared to their counterpart AT starches, whereas the reverse was observed for waxy corn starch. Enthalpy of gelatinization (ΔH<SUB>gel</SUB>) was lower in AT normal and waxy starches as compared to their native starches. The percentage of retrogradation (%R) was significantly higher for native corn starches as compared to their AT starches. A significant reduction in peak-(P<SUB>V</SUB>), trough-(T<SUB>V</SUB>), breakdown-(B<SUB>V</SUB>), final-(F<SUB>V</SUB>), and setback viscosity (S<SUB>V</SUB>) was observed by acid thinning, and the reduction was more pronounced in AT waxy starches. Among AT starches, AT waxy starch showed the lowest values of P<SUB>V</SUB>, T<SUB>V</SUB>, B<SUB>V</SUB>, F<SUB>V</SUB> and S<SUB>V</SUB>.

Calcium - Boron Interaction in Exopolysaccharide Production by the Cyanobacterium , Nostoc spongiae forme

(Singh),(Neetu),(R . K . Asthana),(S . P . Singh) 한국미생물생명공학회 2000 Journal of microbiology and biotechnology Vol.10 No.3

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PL and ESR of Gd3+ in LaMgAl11O19 phosphors

Singh, Vijay,Singh, N.,Pathak, M. S.,Watanabe, S.,Gundu Rao, T. K.,Singh, Pramod K.,Kwon, Young-Wan Springer-Verlag 2018 Journal of materials science Materials in electron Vol.29 No.6

<P>LaMgAl11O19 doped with different concentrations of gadolinium phosphors were synthesized by combustion and characterized using X-Ray diffraction to identify the crystalline phase. Photoluminescence studies on the sample showed emission peaks at 313 and 306 nm with lambda(exi) = 273 nm corresponding to the P-6 (J) -> S-8(7/2) transitions of Gd3+ ions. In phosphors with low dopant concentrations, dominant electron spin resonance lines are observed with g (eff) similar to 1.96, 1.98, 4.2, and 6.0. With increasing concentrations, the spectrum appears to be U-shaped, and main lines are seen at g (eff) similar to 1.98, 2.04, 2.8, 4.1 and 6.2. Distortions in the immediate environment of Gd3+ ions lead to relatively strong crystal fields and the appearance of lines in the low field region of the spectrum.</P>

SOME POINT ESTIMATES FOR THE SHAPE PARAMETERS OF EXPONENTIATED-WEIBULL FAMILY

UMESH SINGH,PRAMOD K. GUPTA,S. K. UPADHYAY 한국통계학회 2006 Journal of the Korean Statistical Society Vol.35 No.1

Maximum product of spacings estimator is proposed in this paper asa competent alternative of maximum likelihood estimator for the parame-ters of exponentiated-Weibull distribution, which does work even when themaximum likelihood estimator does not exist. In addition, a Bayes type esti-mator known as generalized maximum likelihood estimator is also obtainedfor both of the shape parameters of the aforesaid distribution. Though, theclosed form solutions for these proposed estimators do not exist yet thesecan be obtained by simple appropriate numerical techniques. The relativeperformances of estimators are compared on the basis of their relative riskeciencies obtained under symmetric and asymmetric losses. An examplebased on simulated data is considered for illustration.AMS 2000 subject classications.Primary 62F10, 62F15, 93B40; Secondary 65C10,62N99.Keywords. Maximum product of spacings estimators, generalized maximum likelihoodestimators, maximum likelihood estimator, squared error loss function, LINEX loss func-tion, relative risk eciency, non-informative prior.1. IntroductionThe data obtained from lifetime experiments are referred to as failure timedata and such failure time data, results from dierent lifetime experiments con-ducted under sophisticated controlled and complex environments, exhibit dier-ent ypes of failure rates, which are generally categorized as, constant, monotoneReceived November 2004; accepted December 2005.yThis work was supported by Senior Research Fellowship (S.R.F), funded by Council ofScientic and Industrial Research (C.S.I.R.), India.

Limitations in doxorubicin production from Streptomyces peucetius

Malla, S.,Prasad Niraula, N.,Singh, B.,Liou, K.,Kyung Sohng, J. G. Fischer 2010 Microbiological research Vol.165 No.5

Doxorubicin (DXR), produced by Streptomyces peucetius ATCC 27952, exhibits potent antitumor activity against various cancer cell lines. Considerable time has lapsed since the biosynthesis of DXR and its overproduction was first summarized. Based on biosynthetic studies and product analysis, various factors affecting its production by the parental strain, S. peucetius ATCC 27952, are reviewed to better circumvent any bottlenecks in DXR production, thereby providing ideas to genetically engineered industrial strains of S. peucetius.