Bhabani Shankar Panigrahi

Silica-Coated Europium-Doped Gadolinium Oxide Nanorods for Dual-Modal Imaging of Cancer Cells

Dual-modal imaging of cancer cells is possible with the silica-coated europium-doped gadolinium oxide nanorods due to their magnetic and luminescent properties. In the synthesized nanorods, europium ions serve as ‘luminescent centers’ facilitating optical imaging and gadolinium oxide acts as the contrast agent for magnetic resonance imaging (MRI). This article reports the synthesis method of the europium-doped gadolinium oxide (Eu:Gd2O3) nanorods by the co-precipitation method. The prepared nanorods are further coated with silica to improve its biocompatibility. From the x-ray diffraction (XRD) data, the crystallinity was found to decrease due to the amorphous nature of the silica. Transmission electron microscopy (TEM) studies show that Eu:Gd2O3 nanorods with a length of ∼600nm and diameter of ∼40nm were formed. Silica was coated uniformly with the thickness of ∼15nm. Fourier transform infrared spectroscopy (FTIR) confirms the presence of silica in the prepared nanorods. Emission at 611nm due the presence of Eu3+ ions was observed. The life time of uncoated and silica-coated nanorods was calculated to be 1.1ms and 0.9ms, respectively. In vitro cytotoxicity of the synthesized nanorods in MG63 (human osteosarcoma cell line) was assessed by MTT assay. In vitro MRI studies reveal that the prepared nanorods can be used for T1 contrast enhancement.

Boiler Water Treatment

Abstract Role of water chemistry is very crucial for safe and efficient operation of vital components in feedwater–steam circuit. Proper maintenance of water chemistry helps in minimizing corrosion, deposition, and scaling problems in boiler and turbine and prevents costly shutdown and material replacement. pH, cationic conductivity, iron, copper, chloride, dissolved oxygen, silica, and hydrazine are to be monitored and maintained within technical specification limits for trouble-free operation of boiler. Feedwater should be maintained at high purity level and proper care is to be taken during the production stage itself. Demineralization by ion exchange process using gel-type ion exchange resins is suitable for producing high pure water on large scale. Full flow condensate polishing unit (CPU) having macroporous ion exchange resins is suitable for online purification of condensate to remove the corrosion products generated in the steam–water circuit. CPU is also useful in extending the duration of boiler operation during condenser tube leak. Also, high purity of conditioning chemicals like hydrazine and ammonia is to be maintained. This chapter details the basics and practical aspects of boiler water treatment.

Mechanism of photo-stimulated luminescence in copper and europium doped alkali halide phosphors

Abstract The mechanism of Photo-stimulated Luminescence (PSL) is investigated in copper and europium doped KCl. Electron Paramagnetic Resonance, Photoluminescence, and X-ray Photoelectron Spectroscopy measurements were performed on powdered samples of KCl: Cu+ and KCl: Eu2+, γ-irradiated at room temperature. Our results show that the charge state conversion of Cu+ to Cu2+ does not take place after γ-irradiation in KCl: Eu2+, even though a significant reduction in Eu2+ concentration is detected after γ-irradiation, the PSL is not due to Eu3+-F recombination. The energy transfer from recombination process involving F centers to the activator ions Cu+ and Eu2+ in KCl seems to cause the PSL in these materials.

Synthesis, characterization and photo luminescence studies of uranyl doped SrBPO5

SrBPO5: UO22+ was synthesized using solid state reaction method and characterized using powder X-ray diffraction. PXRD data showed the formation of single phase confirming successful doping of UO22+. Photo luminescence investigation informed stabilization of Uranium as Uranyl (UO22+) in SrBPO5 matrix. Luminescence decay time data suggested two possible environments for UO22+ with two different life time values.

Luminescence studies on photostimulable phosphor CsBr:Eu2+

Photostimulable phosphor CsBr:Eu2+ is prepared through a solid-state reaction. The effect of annealing atmosphere on photoluminescence and photostimulated luminescence was investigated. Optimum luminescence intensity was obtained when samples were prepared at 350°C in air atmosphere. The effect of irradiation of gamma and neutron had resulted in the formation of optically stimulable traps with different trap depths. The role of monovalent and divalent dopants on thermoluminescence dosimetric properties has been discussed.