Characterization of noise and design of active noise control technology in longwall mines

Production and safety have always been a prime issue for mining industry and mining engineers, who strive hard to achieve the critical balance between them. Hearing loss and uneasy working environment are few common ones affecting the health statistics of a underground mine. As a result, recent years there have been the focus on to develop an engineering controls to reduce the underground noise. Unique work has been done in this thesis to add additional information on the active noise control technology applied to Longwall mining operations.;Mostly, the survey results indicated that the frequency content of each noise and the number of events decide on the effect on worker. Also, in Stage loader the Lower frequencies showed a significant contribution to the overall sound pressure level (SPL). However, under some combinations the contribution of higher frequencies cannot be denied. Based on these findings, Active Noise Control (ANC) set-up was prepared for canceling the unwanted frequencies and reduces the overall sound pressure level. It was also found that the ANC was more effective for the lower frequencies ranging from 100 Hz to 700 Hz and cancellations were more significant for the low frequencies than for the higher ones. (Abstract shortened by UMI.)

Genotype and environment interaction and stability analysis for seed yield in yellow mung bean (Vigna radiata L.)

Nine yellow seeded mung (Vigna radiata L.) genotypes were evaluated along with three checks for their yield performance during three years (2007, 2010 and 2011). Pooled analysis of variance and stability analysis were performed. The genotypic (G) × environment (E) interaction and both variance due to genotypes and environment were significant. The portioning of G × E interaction into linear and non-linear components indicated that both predictable and unpredictable components shared the interaction. On the basis of stability parameters, the top yielding genotypes such as BGS-9 (605.444 Kg/Ha), Sel-4 (519.778 Kg/Ha) and China mung (567.000 Kg/Ha) exhibited high mean yield. Based on stability parameters the genotypes YM-5 (459.889 Kg/Ha), YM-8 (451.333 Kg/Ha) exhibited low mean performance along with regression value nearer to unity (bi=1) and non significant deviation from regression (S2 di=0) indicating the high stability and wider adaptability across the three environments. The genotypes BGS-9 (605.444 Kg/Ha) and Sel-4 (519.778 Kg/Ha) exhibited high mean value and bi values (bi>1) and non significant deviation (S2 di < 0) value indicating adapted for high performance environments (These genotypes are sensitive to environments and give maximum yield when inputs are not limited)

PHYTOCHEMICAL EVALUATION AND IN VITRO ANTIMICROBIAL AND ANTIOXIDANT STUDIES OF LEAF AND STEM BARK EXTRACTS OF POLYALTHIA FRAGRANS (DALZ.) BEDD.–AN ENDEMIC SPECIES OF WESTERN GHATS

Objective: Phytochemical constituents of various solvent extracts of leaf and stem bark of Polyalthia fragrans (Dalz.) Bedd were screened. Antimicrobial and antioxidant activities of the extracts were evaluated.Methods: Crude extracts of methanol, ethyl acetate, chloroform and aqueous of leaf and stem bark were evaluated for antimicrobial activity by disc diffusion method and antioxidant activity by DPPH (diphenyl-2-picrylhydrazyl) radical scavenging and reducing power assay. Quantitative analysis of total phenolics was done by the Folin-Ciocalteau method and total flavonoids by aluminum chloride method.Results: The study revealed the presence of several physiologically active phytochemicals such as alkaloids, phenols, flavonoids and tannins. The highest antibacterial activity of methanol extract of the leaf was observed against Bacillus subtilis with 14.33±0.57 mm inhibition zone and water extract of stem bark against Proteus vulgaris with 17.67±1.52 mm inhibition zone among other extracts. The lowest activity of leaf methanol and leaf water extract was observed against Bacillus subtilis. The IC50 values of 58.18±2.04 µg/ml, 116.58±2.43 µg/ml, 134.78±3.64 µg/ml and 387.28±2.9 µg/ml for DPPH activity were observed in methanol stem bark, ethyl acetate stem bark, methanol leaf and ethyl acetate leaf extracts respectively. The reducing power of extracts was very potent which increased with increasing concentrations of the sample.Conclusion: The results indicate that phytochemicals like alkaloids, phenols, flavonoids and tannins may be responsible for the antimicrobial and antioxidant properties. The results suggest that P. fragrans can be further researched to be used as a natural source of a potent drug by mankind

Onset of Benard-Marangoni Ferroconvection with Internal Heat Generation

The effect of internal heat generation on the onset of Benard-Marangoni convection in a horizontal ferrofluid layer heated from below in the presence of a uniform vertical magnetic field is studied. The lower boundary is rigid and the upper free boundary is assumed to be flat and undeformable. Both the boundaries are considered to be perfectly insulated to temperature perturbations and the resulting eigenvalue problem is solved numerically using the Galerkin technique as well as analytically by regular perturbation technique with wave number as a perturbation parameter. It is observed that the analytical results agree well with those obtained numerically. It is noted that the combined effect of magnetic Rayleigh number and dimensionless internal heat source strength is to reinforce together and to hasten the onset of Benard-Marangoni ferroconvection compared to their presence in isolation. In addition, the nonlinearity of fluid magnetization is found to have no influence on the criterion for the onset of ferroconvection. Some existing results are reproduced as particular cases from the present study

A REVIEW ON NATURAL COMPOSITES

Natural fibers have attracted the interest to engineers, researchers, professionals and scientists all over the world as an alternative reinforcement, because of its superior properties such as high specific strength, low weight, low cost, fairly good mechanical properties, non abrasive, eco-friendly and bio-degradable characteristics. A brief review has been carried out to make use of the natural fibers (such as abaca, jute, cotton, coir, Glass fiber etc) abundantly available in India. This paper presents a review on the mechanical properties of Abaca, Jute, Glass fibre

The RESPONSE OF SUGARCANE GENOTYPES SUBJECTED TO SALINITY STRESS AT DIFFERENT GROWTH PHASES: RESPONSE OF SUGARCANE GENOTYPES SUBJECTED TO SALINITY STRESS AT DIFFERENT GROWTH PHASES: Abstract, Introduction,materials & Methods, Resultls & Discussion, Conclusion.

 A few commercial sugarcane genotypes were subjected to salinity stress at various growth phases of sugarcane to ascertain the critical growth stage for salinity stress and to assess the response of the genotypes. All the data were recorded and analysed during maturity phase. The salt treatments drastically reduced SPAD chlorophyll, chlorophyll fluorescence, RWC, stalk height, weight and other yield parameters in a few genotypes during T2 (salt treatment given during formative phase) & T5 (salt treatment given throughout crop cycle) but a few genotypes which are tolerant towards salt stress gave better results comparing other genotypes. The ions like sodium, potassium and chloride were analysed in the juice which showed higher elevation in the genotype Co 97010. Among the genotypes, Co 85019 and Co 99004 recorded significantly prime compared to rest of the genotypes. Treatment throughout the growth phases (T5) followed by stress at formative phase (T2) were found to be critical for growth, physiological and yield responses in all the genotypes

Prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) infections among patients admitted in critical care units in a tertiary care hospital

Background: The emergence of Methicillin-resistant Staphylococcus aureus (MRSA) infections in hospital leads to significant morbidity and mortality. Hence the present study was undertaken to estimate the prevalence of MRSA in critical care units (CCUs) at our centre. The objective of this study was to find the prevalence of MRSA infections in CCUs, to determine their antibiotic profile. And to screen for MRSA in the environment of CCUs in order to find whether they act as a source of infection.Methods: The present cross-sectional study included 100 patients admitted to various CCUs in our hospital. The clinical specimens (urine, Sputum, pus, blood and CSF) were collected from the admitted patients along with environmental samples from these CCUs. Two samples were collected from each patient and subjected to culture and antibiotic susceptibility testing.Results: 168 samples from 100 patients were processed. Out of which five pus samples from five different patients admitted in surgical intensive care unit (SICU) were positive for MRSA infection showing 5% prevalence in CCUs. All MRSA strains were sensitive to vancomycin and teicoplanin. Out of 30 environmental swabs, 1 swab taken from paediatric intensive care unit (PICU) showed positivity for MRSA (3%).Conclusions: CCUs in our hospital have shown 5% prevalence of MRSA among the admitted patients. There was no correlation between environmental MRSA presence and infection in the samples from patient