Controlling the size distribution of nanoparticles through the use of physical boundaries during laser ablation in liquids

A simple, yet effective method of controlling the size and size distributions of nanoparticles produced as a result of laser ablation of target material is presented. The method employs the presence of physical boundaries on either sides of the ablation site. In order to demonstrate the potential of the method, experiments have been conducted with copper and titanium as the target materials that are placed in two different liquid media (water and isopropyl alcohol). The ablation of the target material immersed in the liquid medium has been carried out using an Nd:YAG laser. Significant differences in the size and size distributions are observed in the cases of nanoparticles produced with and without confining boundaries. It is seen that for any given liquid medium and the target material, the mean size of the nanoparticles obtained with the boundary-fitted target surface is consistently higher than that achieved in the case of open (flat) targets. The observed trend has been attributed to the plausible role(s) of the confining boundaries in prolonging the thermalisation time of the plasma plume. In order to ascertain that the observed differences in sizes of the nanoparticles produced with and without the presence of the physical barriers are predominantly because of the prolonged thermalisation of the plasma plume and not due to the possible formation of oxide layer, select experiments with gold as the target material in water have also been performed. The experiments also show that, irrespective of the liquid medium, the increase in the mean size of the copper-based nanoparticles due to the presence of physical boundaries is relatively higher than that observed in the case of titanium target material under similar experimental conditions.Comment: 24 pages, 9 figures, a part of this work has been published in Photonics Prague 2017, (Proc. SPIE 10603, Photonics, Devices, and Systems VII, 1060304) titled "A novel method for fabrication of size-controlled metallic nanoparticles

Assessment of groundwater quality status by using water quality index (WQI) and geographic information system (GIS) approaches: a case study of the Bokaro district, India

Abstract One hundred two groundwater samples were collected from the Bokaro district of Jharkhand state, India, during the pre-and post-monsoon seasons of the year 2014–2015. In the present study, groundwater samples were analysed for pH, TDS, TH, Ca2+, Mg2+, Na+, K+, Cl−, SO4 2−, HCO3 −, F− and NO3 − to evaluate the suitability of the groundwater for drinking purposes through geographic information system (GIS)-based water quality index (WQI) model. For quality assessment, values of analysed parameters of the groundwater samples were compared with the Bureau of Indian standards (BIS) and World Health Organization (WHO) water quality standards. The analytical results indicate slightly acidic to slightly alkaline nature of the groundwater in the study area. Concentrations of Ca2+, Mg2+, HCO3 −, F−, NO3 −, TDS and TH exceeded the desirable as well as permissible limits of drinking water quality standards recommended by the BIS (Indian Standard Drinking Water Specification, 2012) and WHO (Guidelines for drinking water quality: training pack, WHO, Geneva, 2004) in the study area during the pre- and post-monsoon seasons, respectively. However, Na+, K+, Cl− and SO4 2− concentrations were within the permissible limits during both seasons. The hydrochemical analysis of the studied groundwater samples documented with ternary and Durov diagram revealed that most of the groundwater samples belong to HCO3 − type of anions facies and no dominant type of cation facies. The GIS-based WQI maps for the study area indicate that the poor quality of water was found the maximum in the pre-monsoon season as compared to the post-monsoon season in the study area, respectively. The high values of WQI in the several groundwater samples of the Bokaro district indicate that water is not suitable for direct consumptions and it required sustainable treatment before its utilization for drinking uses

Identification of suitable locations for artificial groundwater recharge in a mining area of India by using remote sensing and GIS techniques

Mining is one of the major activities causing water pollution and threating the quality and quantity of surface and groundwater resources in many parts of the world. Mining and related activities also damage the aquifer and decrease the water availability in the area. Groundwater may be considered as one of the most precious and basic needs for human existence and the survival of people providing the luxuries and comforts in addition to fulfilling the basic necessities of life. In India, more than 90% of the rural and nearly 30% of the urban populations depend on groundwater for drinking and domestic requirements. Historically, the overexploitation of groundwater resources is a major issue in Indian country. In fact in the last decades annual water demand has increased for agricultural and industrial activities. The hydrogeological system characterization and the artificial recharging of aquifers might help to solve the problem of the groundwater level decreasing. For this purpose, six important hydrogeological factors such as slope, infiltration, drainage, depth to groundwater, land use and geology have been considered to define the most suitable locations for artificial groundwater recharge in mining area. Different thematic maps were prepared from existing maps and data sets, remote-sensing images, and field investigations for identification of suitable locations for artificial recharge. Thematic layers for these parameters were organized as raster data, classified, weighted and integrated in a GIS environment using of Boolean and Fuzzy logic. The main objective of the present study is identifying artificial recharge site in West Bokaro coalfield of Jharkhand state using remote sensing and GIS applications, in order to make a proper planning and sustainable management of groundwater resources

Green synthesis of acetohydroxamic acid by thermophilic amidase of Bacillus smithii IIIMB2907

373-377Acetohydroxamic acid is a pharmaceutically active metal chelating agent which has various applications in the field of medicine. Current study focuses on the enzymatic synthesis of acetohydroxamic acid catalysed by thermophilic amidase from Bacillus smithii IIIMB2907. Bacterial cells were grown in 7 L fermenter for amidase production and effect of pH, temperature and substrate concentration for the biotransformation of acetamide to acetohydroxamic acid was studied. Batch reaction was also successfully optimized at bench scale with the recovery of ≈ 81% acetohydroxamic acid (purified)

Green synthesis of acetohydroxamic acid by thermophilic amidase of Bacillus smithii IIIMB2907

Acetohydroxamic acid is a pharmaceutically active metal chelating agent which has various applications in the field of medicine. Current study focuses on the enzymatic synthesis of acetohydroxamic acid catalysed by thermophilic amidase from Bacillus smithii IIIMB2907. Bacterial cells were grown in 7 L fermenter for amidase production and effect of pH, temperature and substrate concentration for the biotransformation of acetamide to acetohydroxamic acid was studied. Batch reaction was also successfully optimized at bench scale with the recovery of ≈ 81% acetohydroxamic acid (purified)

Identification of artificial groundwater recharging zone using a GIS-based fuzzy logic approach: a case study in a coal mine area of the Damodar Valley, India

Abstract The West Bokaro coalfield is a richest coal-mining belt in the Damodar Valley, India. The extensive mining of the area has resulted in disruption of the groundwater availability in terms of both quantity and quality. This has led to a drinking water crisis, especially during the pre-monsoon period in the West Bokaro coalfield area. The characterization of the hydrogeological system and the artificial recharging of the aquifers might help to better manage the problem of the groundwater-level depletion. For this purpose, seven important hydrogeological factors (water depth, slope, drainage, soil, infiltration, lithology, and landuse) have been considered to define the most suitable locations for artificial groundwater recharging in the mining area. Different thematic maps were prepared from existing maps and data sets, remote-sensing images, and field investigations for identification of the most suitable locations for artificial recharge. Thematic layers for these parameters were prepared, classified, weighted, and integrated into a geographic information system (GIS) environment by means of fuzzy logic. The results of the study indicate that about 29 and 31% of the area are very suitable and suitable for recharging purposes in the West Bokaro coalfield. However, the rest of the area is moderate to unsuitable for recharging due to the ongoing mining and related activities in the study area. The groundwater recharging map of the study area was validated with measured electrical conductivity (EC) values in the groundwater, and it indicated that validation can be accepted for the identification of groundwater recharging sites. These findings are providing useful information for the proper planning and sustainable management of the groundwater resources in the study area

Identification of suitable locations for artificial groundwater recharge in a mining area of India by using remote sensing and GIS techniques

Mining is one of the major activities causing water pollution and threating the quality and quantity of surface and groundwater resources in many parts of the world. Mining and related activities also damage the aquifer and decrease the water availability in the area. Groundwater may be considered as one of the most precious and basic needs for human existence and the survival of people providing the luxuries and comforts in addition to fulfilling the basic necessities of life. In India, more than 90% of the rural and nearly 30% of the urban populations depend on groundwater for drinking and domestic requirements. Historically, the overexploitation of groundwater resources is a major issue in Indian country. In fact in the last decades annual water demand has increased for agricultural and industrial activities. The hydrogeological system characterization and the artificial recharging of aquifers might help to solve the problem of the groundwater level decreasing. For this purpose, six important hydrogeological factors such as slope, infiltration, drainage, depth to groundwater, land use and geology have been considered to define the most suitable locations for artificial groundwater recharge in mining area. Different thematic maps were prepared from existing maps and data sets, remote-sensing images, and field investigations for identification of suitable locations for artificial recharge. Thematic layers for these parameters were organized as raster data, classified, weighted and integrated in a GIS environment using of Boolean and Fuzzy logic. The main objective of the present study is identifying artificial recharge site in West Bokaro coalfield of Jharkhand state using remote sensing and GIS applications, in order to make a proper planning and sustainable management of groundwater resources

Coronarin K and L: Two Novel Labdane Diterpenes From Roscoea purpurea: An Ayurvedic Crude Drug

The main objective of cancer treatment with chemotherapy is to kill the cancerous cells without affecting the healthy normal cells. In the present study, bioactivity-guided purification of the n-chloroform soluble fraction from the methanol extract of Roscoea purpurea resulted in the identification of two new labdane diterpenes: coronarin K (1) and coronarin L (2), along with eight known compounds, coronarin A (3), bisdemethoxycurcumin (4), kaempferol 3-O-methyl ether (5), kaempferol (6), fenozan acid (7), 3-(3-methoxy,4-hydroxyphenyl)-2-propenoic acid ferulic acid (8), caffeic acid (9), and gallic acid (10). The structural identification of new compounds (1 and 2) were determined by detailed analysis of 1D (1H and 13C) and 2D NMR (COSY, HSQC, and HMBC) spectroscopic data. The relative configurations of 1 and 2 were determined with the help of NOESY correlations and comparison of optical rotations with known labdane diterpenes, with established stereochemistry, while structure of known compounds was established by direct comparison of their NMR data with those reported in the literature. This is the first report of isolation of this labdane diterpenes and phenolic classes of secondary metabolites in R. purpurea. In the preliminary screening, the methanol extract and its fractions were tested for the cytotoxic activity against a panel of four cancer cell lines (A549, HCT-116, Bxpc-3, and MCF-7); extract and its chloroform fraction were found to be active against the lung cancer cell line, A-549, with IC50 value <25 μg/ml. Owing to the notable cytotoxic activity of the chloroform fraction, the compounds (1–5) were screened for their cytotoxicity against all the cell lines by MTT assay. Coronarin K, 1 showed significant cytotoxic potential against lung cancer cell lines (A-549), with IC50 value of 13.49 μM, while other compounds did not show activity below 22 μM

Spontaneous Rectal Perforation with Transanal Evisceration of the Small Bowel: A Rare Case Report

Transanal evisceration of the small bowel is a rare surgical emergency. Rectal perforation in such cases is usually due to an underlying rectal prolapse. We report a case of a middle aged (45 years) male with spontaneous rectal perforation and transanal evisceration of the small bowel. Approximately 150 cm of small bowel had eviscerated transanally and the patient required emergent abdominal exploration, reposition of the small bowel, and repair of the rectal perforation. Small bowel evisceration through the anal verge is an emergent condition and the aim was to prevent life threatening complications related to sepsis

Status of Noise Exposure in Cement Preparation Plant - A Case Study

Noise is a compratively a newly recognised problem in the list of occupational hazards. The noise level of different types of machines in a cemetn proparation palnt was measrued during the period of three months. The different sources prducing noise levels above 90 dBA were identified and a typical frequency spectrum produced by machine when, it was in operation was recorded. Noise exposure index (NEI) were calculated and found that NEI velue is higher than the prescribed limits. The results of the sudy carried out have been presented in this paper