Multi-objective optimization in WEDM of D3 tool steel using integrated approach of Taguchi method & Grey relational analysis

In this paper, wire electrical discharge machining of D3 tool steel is studied. Influence of pulse-on time, pulse-off time, peak current and wire speed are investigated for MRR, dimensional deviation, gap current and machining time, during intricate machining of D3 tool steel. Taguchi method is used for single characteristics optimization and to optimize all four process parameters simultaneously, Grey relational analysis (GRA) is employed along with Taguchi method. Through GRA, grey relational grade is used as a performance index to determine the optimal setting of process parameters for multiobjective characteristics. Analysis of variance (ANOVA) shows that the peak current is the most significant parameters affecting on multi-objective characteristics. Confirmatory results, proves the potential of GRA to optimize process parameters successfully for multi-objective characteristics

A Modular and Integrated Optimisation Model for Underwater Vehicles

A modular and integrated optimisation model for the design of underwater vehicles is presented. In the proposed optimisation model two modules (i.e. low fidelity and high fidelity) are incorporated and the basic geometric definition of computer aided design (CAD) is integrated with computational fluid dynamic (CFD) analysis. The hydrodynamic drag is considered as single objective with constraints on the geometric parameters of dimension, space and volume. The CAD model is implemented in MATLAB*TM and CFD model is implemented in Shipflow**TM. A real-world design example of an existing underwater vehicles is presented. The applicability of proposed optimisation model is shown. The presented results show that within given set or sets of constraints the application of optimisation model in design results into an efficient hull form.

A Cross-Sectional Study to Assess Awareness and Practices Related to Prevention of COVID-19 Amongst Local Vendors around Medical and Dental Establishments

INTRODUCTION: Even as the world is returning to normalcy after COVID-19, there is still a need to be cautious and adopt proper hygiene practices and social distance norms. AIM: To assess the awareness and practices related to prevention of Covid-19 amongst local vendors around medical and dental establishments in Northern India. MATERIALS AND METHOD: This cross-sectional study was conducted over a period of  one month using a pre-tested and pre-validated questionnaire. Vendors near ten medical and dental establishments in north India were contacted by standardized volunteers to prevent bias. They were located within the range of 250 meters on both sides of these facilities through convenience sampling.  Data was coded, entered in MS excel, descriptive statistics were applied. Statistical tests included the student’s independent t-test and multiple logistic regression. P value was kept significant at <0.5 and software used was SPSS version 23.0. RESULTS: Most vendors were males (76.7%), were operating shops on rent (47.7%) and had passed middle school (40.2%). A Majority of them were aware of common symptoms (99.4%), while 90.1% were aware about the mode of transmission. All vendors knew about the availability of the vaccine (100%). and 78.2% of the vendors were fully vaccinated, while 04 (1.3%) were not vaccinated yet. However, only 60% (p=0.03) of the vendors practised hand washing, distancing from sick, no handshake, use a cloth while coughing/sneezing as preventive measures. CONCLUSION: There is still a need for continuous education of the food vendors regarding proper and hygienic practices as well as mask wearing to fight off this dreaded pandemic and return to normalcy as soon as possible

Effect of Methyl Parathion on Survival and Development of Tadpoles of Indian Cricket Frog Fejervarya Limnocharis

Amphibian populations are declining due to various causes including pesticide contamination in natural habitat. We evaluated effect of Methyl Parathion (MPT) an organophosphate pesticide on survival and development of common paddy field frog Fejervarya limnocharis in a laboratory condition. Effect of 0 µg MPT/L, 500 µg MPT/L, 1000 µg MPT/L, 1500 µg MPT/L, 2000 µg MPT/L and 3000 µg MPT/L was studied using static toxicity test for a duration of 28 days. MPT reduced the survival of tadpole. The mortality increased with the increased concentration of pesticide. The development decreased with increased MPT concentrations. At higher concentrations, MPT induced slow development and tadpoles failed to metamorphose. It is assumed that slow development could affect the larval life and amphibian population in agro-ecosystem

Effects of Transport Coherence on the Mutual Annihilation of Excitons

We report results of a theoretical investigation into the mutual annihilation of tight-binding excitons. The results are in apparent contradiction with intuitive expectations and provide corrections to expressions given by one of the present authors (V.M.K.) in an earlier analysis. A part of that analysis was based on a mapping of the dynamics of two mobile, mutually annihilating excitons onto the dynamics of a single exciton migrating in the presence of a fixed trap. We find that while this equivalence is valid for incoherent, randomly walking particles in an ordered system, it does not hold for an arbitrary degree of transport coherence. Any nonvanishing coherence makes a moving trap, i.e., a second exciton, less effective than the corresponding stationary trap. For realistic intersite interactions, the quantum yield for annihilation passes through a maximum, i.e., the fluorescence yield passes through a minimum, as the exciton motion becomes less coherent. The earlier predictions are recovered in the incoherent limit

Validation of body fat measurement by skinfolds and two bioelectric impedance methods with DEXA - the Chennai Urban Rural Epidemiology Study [CURES-3]

Background and Objective: Although Asian Indians have been shown to have increased body fat compared to Europeans, there have been very few studies in Asian Indians validating the various methods available for body fat measurement. The aim of this study was to test the validity of body fat measured by two commercial impedance analyzers (leg-to-leg and hand-held) as well as by skinfolds with Dual Energy Xray Absorptiometry (DEXA) as the reference method in a population based study in southern India. Methods: Body fat percentage (BF%) was measured in 162 South Indian urban men (n=76) and women (n=86) randomly selected from the "Chennai Urban Rural Epidemiology Study" (CURES), an ongoing population based study of a representative population of Chennai. The mean age of the subjects was 45.1 ± 9.0 years and the body mass index ranged from 16.4 - 34.4 kg/m2. Percentage body fat was measured using DEXA, segmental impedance (leg-to-leg: BF%IMP-LEG; and hand-held BF%IMP-HAND) using the manufacturer's software and skinfolds using the prediction equation from the literature (BF%SKFD). Results: Body fat (%) determined by the leg-to-leg method (BF%IMP-LEG 35.10 ± 7.26) and the skinfolds (BF%SKFD 35.77 ± 6.06) did not differ significantly from the reference method DEXA (BF%DEXA 35.82 ± 8.33), but the hand-held impedance method (BF%IMP-HAND 31.38 ±6.24) showed significant difference (p < 0.001). The bias for estimation of body fat (%) for the bioimpedance leg-to-leg, hand-held and skinfolds were 0.73 ± 5.70, 4.45 ± 4.83 and 0.06 ± 5.86 respectively. All the three methods showed a fairly good correlation with DEXA (BF%IMP-LEG : r = 0.741, p<0.001; BF%IMP-HAND : r = 0.817, p< 0.001; BF%SKFD : r = 0.710, p< 0.001). Conclusion: The study shows that in urban south Indians, measurement of body fat by the leg-to-leg impedance and the skinfold method have better agreement (lower bias) with DEXA than the hand-held impedance. However, all three methods (skinfolds, the leg-to-leg bioelectric impedance and hand-held impedance) show a fairly good correlation with DEXA

Validation of the modified Berlin questionnaire to identify patients at risk for the obstructive sleep apnoea syndrome

Background & Objectives: Awareness regarding obstructive sleep apnoea (OSA) among general public as well as practicing physicians is low in India. The present study was undertaken to test the utility of modified Berlin questionnaire for risk categorization of OSA in Indian setting. Methods: The modified Berlin questionnaire was administered in 180 middle aged adults (of 320 screened), of whom, 104 underwent overnight polysomnograhy, in a cross-sectional study at a tertiary care, referral center in north India. Questionnaire addressed the presence of frequency of snoring, wake time sleepiness, fatigue, obesity and hypertension. Subjects with persistent and frequent symptoms in any two of these three domains were considered in high risk category for obstructive sleep apnoea. Overnight polysomnograhy was performed to measure apnoea and hypopnoea index (AHI). Results: Questions about the symptoms demonstrated internal consistency (Cronbach alpha correlations 0.92-0.96). Of the 180 respondents to the screening questions, 80 were in the high risk and the rest were in low risk group. For 104 subjects who underwent polysomnograhy, risk grouping was useful in prediction of AHI. High risk category predicted an AHI > 5 with a sensitivity of 86 per cent, specificity of 95 per cent, positive and negative predictive values of 96 and 82 per cent respectively. These results were comparable to Berlin questionnaire study done in the western population for validation. Interpretation & Conclusion: On the basis of the findings of present study it is concluded that administration of modified Berlin questionnaire prior to a polysomnography study can identify high risk subjects and can thus avoid unnecessary polysomnography studies especially in resource-limited settings. To identify subjects at risk for OSA syndrome in general population, this questionnaire can be applied. However, the findings of the present study need to be confirmed further in a large number of subjects in a community-based setting

Total phenolic and flavonoid content, antioxidant effects and antidiarrheal activity of balacaturbhadrika churna – an Ayurvedic preparation

Balacaturbhadrika churna (BC) is an important pediatric preparation in Ayurveda. It is used to treat various diseases of gastro-intestinal tract particularly diarrhea in children. Free radicals cause oxidative damage in the intestine and are correlated with its diseases. In the current study, total phenolic and flavonoid contents of BC extracts were determined and their antioxidant evaluation in various in vitro models was carried out. Procedures mentioned in The Ayurvedic Formulary of India were followed to prepare in-house BC; alcoholic (BCAL) and aqueous (BCAQ) extracts were prepared and tested by standard procedures. BCAL was tested for antidiarrheal activity in castor oil induced model. The ethanolic extract showed better antioxidant activity in many of the models as compared to aqueous extract. The present study showed substantial amounts of flavonoids and phenolics in churna extracts. BCAL showed significant antidiarrheal activity against the tested model. The potential antioxidant and antidiarrheal activities displayed by Balacaturbhadrika churna extracts could be attributed to these contents