Depth Dependence Radon Study in Indian Tube-Wells

Radon a radioactive gas arising from decay of 226 Ra, has been recognized to be one of the major contributors to the natural radiation. In the present investigations, measurements of radon and its progeny were carried out under ground in Indian tube-wells at different depths situated at A.M.U., Aligarh (U.P) India. The twin chamber dosimeter cups were fixed for exposure at a depth of 5 to 35 feet with difference of 5 feet from the surface at three different locations. After exposure, the detectors were retrieved, etched and analyzed in the laboratory for the calculation of radon and its progeny. All the values of the radon concentration presents in this paper are higher than the action level (200-600 Bq.m -3 ) as recommended by ICRP

Calculating the electronic transmission properties of semiconducting carbon nanotube Schottky diodes with increase in diameter

Transmission of twenty-four carbon nanotube geometries to form twelve intramolecular junctions between every two carbon nanotubes have been investigated numerically. The twelve carbon nanotubes are zigzag and rest carbon nanotubes are armchair forming three different kinds of intramolecular junctions named as circumferential defective carbon nanotubes, grouped defective carbon nanotubes and distributed defective carbon nanotubes. Electronic states joining carbon nanotubes form Schottky diode that is analyzed using the tight-binding method. These quantum transmissions through Schottky diodes have been compared among the different defective carbon nanotubes and correlated with the pentagon and heptagon that formed in the intramolecular junction. The transmission coefficient of conduction band always simulated less than the transmission coefficient of valence band in each intramolecular junction irrespective of the joining of carbon nanotubes in the Schottky diodes. The maximum asymmetry of distributed defective carbon nanotubes in transmission is observed more clearly than that for other two defective carbon nanotubes forming Schottky diodes. It is interesting to note that the position of the localized states above and below the Fermi energy level may be controlled with the distribution of the defect pairs and the hexagons around the defects in the defected carbon nanotube

High-energy ball milling technique for ZnO nanoparticles as antibacterial material

Nanoparticles of zinc oxide (ZnO) are increasingly recognized for their utility in biological applications. In this study, the high-energy ball milling (HEBM) technique was used to produce nanoparticles of ZnO from its microcrystalline powder. Four samples were ball milled for 2, 10, 20, and 50 hours, respectively. The structural and optical modifications induced in the ‘as synthesized’ nanomaterials were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and photoluminescence emission spectra (PL). SEM and TEM results show a gradual decrease in particle size from around 600 to ∼30 nm, with increased milling time. The initial microstructures had random shapes, while the final shape became quite spherical. XRD analysis showed ZnO in a hexagonal structure, broadening in the diffracted peaks and going from larger to smaller particles along with a relaxation in the lattice constant c. The value of c was found to increase from 5.204 to 5.217 Å with a decrease in particle size (600 to ∼30 nm). PL result showed a new band at around 365 nm, whose intensity is found to increase as the particles size decreases. These remarkable structural and optical modifications induced in ZnO nanoparticles might prove useful for various applications. The increase in c value is an important factor for increasing the antibacterial effects of ZnO, suggesting that the HEBM technique is quite suitable for producing these nanoparticles for this purpose

Synthesis and optoelectrical properties of f-graphene/cadmium selenide hybrid system

The present work demonstrates the synthesis of a hybrid accepter material containing amino-functionalized graphene oxide (GO) and an inorganic semiconducting material, cadmium selenide (CdSe). First, amino-functionalized graphene was synthesized and then nanocrystals (NCs) of CdSe were in situ grown in the functionalized-(GO) matrix named f-GCdSe. Structural studies such as x-ray diffraction, and a scanning electron microscopic were employed to investigate the growth of CdSe NCs in the graphene matrix. To understand the charge generation and transfer process at the donor/acceptor interface, the absorption, photoluminescence (PL), and transient absorption spectroscopic (TAS) studies have been carried out in poly(3-hexylthiophene) (P3HT)/f-GCdSe thin films. PL quenching in P3HT/f-GCdSe thin film suggests that charge transfer takes place at the donor/acceptor interface. TAS shows higher optical density and long lived free carriers for P3HT/f-GCdSe thin film. These results suggest that f-GCdSe is an excellent electron-acceptor material for organic photovoltaic devices. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Microstructural and optical properties of CuS nanoparticles prepared by sol–gel route

This paper demonstrates the synthesis of CuS nanoparticles using sol–gel route in the presence of distilled water at 100 °C for 3 h. X-ray diffraction (XRD), energy dispersive X-ray spectrum (EDS), and scanning electron microscope (SEM) techniques were employed to study the microstructural properties of the prepared sample. Crystallite size was determined by Debye–Scherrer formula and was found to be 17.73 nm. The EDS spectrum shows a clear peak of Cu and S elements. SEM images show the morphology of the CuS nanostructures. Optical analyses were done by UV–visible and Fourier Transform Infra-Red Spectroscopy (FTIR) techniques. The band gap was calculated by Tauc relation and came out to be 2.89 eV

Synthesis and characterization of Ag nanowires: Improved performance in dye sensitized solar cells

Development of highly efficient dye-sensitized solar cells (DSSCs) with good photovoltaic parameters is an active research area of current global interest. Recently, one dimensional nanomaterial, such as nanorods and nanotubes has replaced the nanoparticles used in DSSCs anode because of their ability to improve the electron transport leading to enhanced electron collection efficiency. In the present work, rapid synthesis of silver nanowires (AgNWs) was done. The XRD characterization was performed to confirm the formation and size of synthesized AgNWs. It was observed that FWHM of the diffraction peaks was increased with AgNWs concentration in TiO2. The synthesized TiO2AgNWs nanocomposite was used as the photo anode of Dye sensitized solar cell. The I–V characteristics of the solar cell were drawn using standard conditions. It was observed that TiO2AgNWs based solar cells have significantly increased photocurrent density resulting in improved conversion efficiency as compared to pure TiO2 based DSSC

Color Centers Formation in Lithium Fluoride Nanocubes Doped with Different Elements

Nanocrystalline cubes of pure and doped LiF material were fabricated. They were doped with Cu, Ag, Dy, Tb, and Eu and studied for their PL properties. Shape of the obtained nanocubes was found to be modified by introducing dopants into the host of LiF. The crystallinity was also decreased by increasing the concentration of these dopants (i.e., Eu and Tb). These impurities could induce exothermic peaks at around 250°C in the measured DSC curves. Moreover, incorporating such impurities into the host of LiF was found to enhance intensity of the broad band at 370–550 nm that was observed in the pure one. Extra sharp emissions were also observed in Eu and Tb doped samples. These results showed that the active color centers created in pure LiF nanocubes can be enriched/enhanced by these impurities, mainly Eu and Tb. This implies that these nanocubes might be useful in the development of optical devices and advanced color center laser