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  • Author: Ajay Kumar x
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Abstract

A case study was carried out to investigate the effectiveness of condition monitoring techniques in the early failure detection of pumps in a thermal power plant. Various condition monitoring techniques used in this case study involved vibration analysis, motor current signature analysis, noise monitoring and wear debris analysis. These techniques were applied on the three pumps, namely boiler feed water pump, auxiliary cooling water pump and condensate extraction pump, which have to work continuously for the operation of the thermal power plant. Vibration analysis of the auxiliary cooling water pump showed that there is a rising trend in the acceleration values at its driving and non-driving end indicating the deterioration of bearings. Motor current index range of all the pumps was found to be within acceptable limits. Wear debris analysis of lubricant in the hydraulic coupling of boiler feed water pump indicated the presence of sand, dirt and low alloy steel sliding wear particles in it. Condition monitoring techniques have been proved to be an effective technique in early failure detection of pumps.

Abstract

Geometrical structures, relative stabilities and electronic properties of neutral, cationic and anionic pure gold Aun+1λ and Ag-doped bimetallic AgAunλ(λ=0,±1;n=1-12) clusters have been systematically investigated by using density functional theory methodology. The optimized structures show that planar to three-dimensional structural transition occurs at n = 5 for cationic clusters. Due to strong relativistic effect of Au clusters, the ground state configurations of neutral and anionic bimetallic clusters favor planar geometry till n = 12. Silver atoms tend to occupy the most highly coordinated position and form the maximum number of bonds with Au atoms. The computed HOMO-LUMO energy gaps, fragmentation energies and second-order difference of energies show interesting odd-even oscillation behavior. The result indicates that AgAu5, AgAu2+ and AgAu2- are the most stable clusters in this molecular system. The DFT based descriptors of bimetallic clusters are also discussed and compared with pure gold clusters. The high value of correlation coefficient between HOMO-LUMO energy gaps and DFT based descriptors supports our analysis. A good agreement between experimental and theoretical data has been obtained in this study.

Abstract

In the present work, static settled concentration, pH and viscosity of bottom ash is studied with addition of additive. Sodium sulfate is used as an additive with proportion of 0.2, 0.4 and 0.6% (by weight). The solid concentration of bottom ash suspension varied from 20 to 50% (by weight). Remarkable improvement has been observed in static settled concentration, pH and viscosity with addition of sodium sulfate with proportion of 0.4%. Reduction in relative viscosity is highly pronounced at higher solid concentration. Similar observation has been reported for static settled concentration and pH of slurry suspension. Addition of additive in bottom ash suspension improves the rheological characteristics which can be beneficial for conveying bottom ash slurry suspension at higher concentration.

Abstract

Due to its large scale applications in the real field, the study of bi-metallic nano-alloy clusters is an active field of research. Though a number of experimental reports are available in this domain, a deep theoretical insight is yet to receive. Among several nano-clusters, the compound formed between Cu–Ag has gained a large importance due to its remarkable optical property. Density Functional Theory (DFT) is one of the most popular approaches of quantum mechanics to study the electronic properties of materials. Conceptually, DFT based descriptors have turned to be indispensable tools for analyzing and correlating the experimental properties of compounds. In this venture, we have analyzed the experimental properties of the (Cu–Ag)n = 1 − 7 nano-alloy clusters invoking DFT methodology. A nice correlation has been found between optical properties of the aforesaid nano-clusters with our evaluated theoretical descriptors. The similar agreement between experimental bond length and computed data is also reflected in this analysis. Beside these, the effect of even-odd alternation behavior of nano compounds on the HOMO-LUMO gap is very important in our computation. It is probably the first attempt to establish such type of correlation.

Abstract

A rust infection was recently observed on Grewia tiliifolia Vahl during an exploration of rust fungi in Himachal Pradesh, India, in October 2015. An examination identified the rust fungus as Puccinia tiliaefolia T. S. Ramakr. & Sundaram. This finding represents a new record for the northwestern Himalayas and the first finding of Puccinia tiliaefolia in India in the last 46 years. A geographical distribution map of P. tiliaefolia is presented.

Abstract

We assessed the impact of socio-economic factors on age at menarche among the adolescent female population from the state of Madhya Pradesh, Central India. Records such as date of birth, chronological age, caste affiliation, size of place of residence, parents’ level of education and occupation, number of siblings, body height and weight, and age at menarche were collected for 330 students of A Central University, Sagar. The impact of socio-economic factors on age at menarche was analysed using analysis of variance. To establish the probability of menarche occurrence at a given age, time-to-event analysis was carried out using Kaplan-Meier curves and the log-rank test for curve comparison. The association between probability of attaining menarche and the independent variables was investigated using Cox proportional-hazard model. ANOVA and the Kaplan-Meier curves showed statistically significant differences in age at menarche according to size of the place of residence, number of siblings, parental level of education, father’s occupation and females’ BMI. The Cox proportional hazard model revealed that father’s occupation was the strongest factor affecting age at menarche among all SES characteristics under study. Irrespective of rapid economic progress over the past few decades, Indian society is still patriarchal with societal male dominance. This translates into participation of fewer women in the paid workforce and labour market, their lower wage rates and smaller contribution to the household budget compared to their male counterparts.

Summary

In this research, the suitability of almond shell and coconut fiber as a renewable agricultural residue for manufacturing of biocomposite to be used as a replacement of wood was investigated. The use of agriculture waste as a reinforcement in composite may result in several environmental and socioeconomic benefits. Biocomposite containing different weight percentage of almond shell particle (10, 20, 30, 40 and 50 wt%) and coconut fiber (2, 4 and 6 wt%) mixed with 20 wt% of almond shell particles were made using epoxy resin and 0.5 wt% of Tricresyl Phosphate. Thermal stability test and morphology (SEM) of the biocomposite were determined.

Abstract

Introduction. Secondary renal amyloidosis due to tuberculosis is a debilitating disease with considerable mortality and morbidity due to renal failure and other manifestations of both amyloidosis and renal failure. Most patients with amyloidosis have been adequately treated with DOTS (Directly observed treatment, Short Course strategy). The aimof our study was to analyze the epidemiological and demographic profile of patients undergoing renal biopsy and found to have renal amyloidosis secondary to tuberculosis.

Methods. In this study, retrospective renal biopsy data was collected from 2009-2012 and patients with amyloidosis were identified and their clinical and biochemical parameters were analyzed.

Results. Incidence of amyloidosis was 4.66% (n=24/514) among total renal biopsies. Among this, secondary amyloidosis constituted 87.5% of total amyloidosis. The commonest etiology in these patients was pulmonary tuberculosis (73.5%). All patients with tuberculosis had previously received DOTS treatment. 47.5% of patients with amyloidosis had renal impairment and 10.5% developed end-stage renal disease over 12 months and were dialysis dependent.

Conclusions. Amyloidosis due to tuberculosis is a well-established, yet under-diagnosed complication of tuberculosis. The duration and treatment status of tuberculosis does not influence the occurrence of amyloidosis, as most of the patients were treated appropriately with DOTS. There are no predictive factors in patients who will develop secondary amyloidosis. At present there is no specific treatment apart from supportive therapy. The prognosis is poor, as most of these patients inexorably progress towards end-stage renal disease (ESRD) with significant mortality and morbidity. To conclude, at present we are only treating tuberculosis, we are yet to cure tuberculosis.