Photoluminescence and thermoluminescence studies of Mg 2 SiO 4 :Eu 3+ nano phosphor

Nanoparticles of Eu 3+ doped Mg 2 SiO 4 are prepared using low temperature solution combustion technique with metal nitrate as precursor and urea as fuel. The synthesized samples are calcined at 800 °C for 3 h. The Powder X-ray diffraction (PXRD) patterns of the sample reveled orthorhombic structure with α-phase. The crystallite size using Scherer's formula is found to be in the range 50–60 nm. The effect of Eu 3+ on the luminescence characteristics of Mg 2 SiO 4 is studied and the results are presented here. These phosphors exhibit bright red color upon excitation by 256 nm light and showed the characteristic emission of the Eu 3+ ions. The electronic transition corresponding to 5 D 0 → 7 F 2 of Eu 3+ ions (612 nm) is stronger than the magnetic dipole transition corresponding to 5 D 0 → 7 F 1 of Eu 3+ ions (590 nm). Thermoluminescence (TL) characteristics of γ-rayed Mg 2 SiO 4 :Eu 3+ phosphors are studied. Two prominent and well-resolved TL glows with peaks at 202 °C and 345 °C besides a shoulder with peak at ∼240 °C are observed. The trapping parameters-activation energy ( E ) , order of kinetics ( b ) and frequency factor ( s ) are calculated using glow curve shape method and the results obtained are discussed

Processing of Graphene/CNT-Metal Powder

In recent days, the demand for powder metallurgy components has increased due to unusual combination of properties. Carbon allotropes such as graphene and CNT are the novel material to enhance the properties of powder metallurgy component. However, processing of such materials is in infancy stage due lack of advance processing technique. This can be addressed through integration of several fabrication techniques to meet the industrial demands. The processing method and its important parameter will define the final property of the component. Such materials have found its applications in various fields like, sports, bio implants, aerospace and automobile sector

A Study Of The Relationship Between Occupational Stress And Emotional Intelligence Of Degree College Teachers

In this study we examined the relationship between occupational stress and emotional intelligence among Degree College Teachers. We also explored the role of socio-demographic factors on occupational stress and emotional intelligence. Samples comprised of 200 college teachers, Karnataka, India (110 males and 90 females) between the age group of 28 to 60 years (mean age =46.7 years) randomly selected from Degree College Teachers affiliated by V.S.K. University. Bellary, India. Tools used for data collection were the (1) Emotional Intelligence Scale (Hyde, Pethe, and Dhar, 2002), (2) Occupational Stress Index (Srivastava and Singh, 1981) and (3) the Personal Information Schedule.Chosen after a comprehensive review of related literature. The samples were contacted individually by the researcher and data was collected through face to face interview. Data collection was spread over a period of one month. Mean, SD, ‘t’ test, and Pearson product moment correlation were the statistical analyses done. From the result we found that emotional intelligence and occupational stress were negatively and significantly related. We also found that socio-demographic variables such as, gender educational qualification, residential status, income and family type were not significant on influence both occupational stress and emotional intelligence. However age had a significant influence on occupational stress and emotional intelligence. However, age had a significant influence on emotional intelligence but was not significant for occupational stress

Ionoluminescence studies of combustion synthesized Dy3+ doped nano crystalline forsterite

Ionoluminescence (IL) of nano crystalline Mg2SiO4:Dy3+ pellet samples bombarded with 100 MeV Si+8 ions with fluences in the range (1.124–22.480) × 1012 ions cm−2 have been studied. Two prominent IL bands with peaks at ∼480 nm and ∼580 nm and a weak band with peak at ∼670 nm are recorded. The characteristic peaks are attributed to luminescence center activated by Dy3+ ions due to the transitions 4F9/2→6H15/2,6H13/2 and 6H11/2. It is found that IL intensity initially decreases rapidly and then continuous to decrease slowly with further increase in ion fluence. The reduction in the Ionoluminescence intensity with increase of ion fluence might be attributed to degradation of Si–O ( 2ν3) bonds present on the surface of the sample and/or due to lattice disorder produced by dense electronic excitation under heavy ion irradiation

Photoluminescence and thermoluminescence studies of Mg2SiO4:Eu3+ nano phosphor

Nanoparticles of Eu3+ doped Mg2SiO4 are prepared using low temperature solution combustion technique with metal nitrate as precursor and urea as fuel. The synthesized samples are calcined at 800 degrees C for 3 h. The Powder X-ray diffraction (PXRD) patterns of the sample reveled orthorhombic structure with alpha-phase. The crystallite size using Scherer's formula is found to be in the range 50-60 nm. The effect of Eu3+ on the luminescence characteristics of Mg2SiO4 is studied and the results are presented here. These phosphors exhibit bright red color upon excitation by 256 nm light and showed the characteristic emission of the Eu3+ ions. The electronic transition corresponding to D-5(0) -> F-7(2) of Eu3+ ions (612 nm) is stronger than the magnetic dipole transition corresponding to D-5(0) -> F-7(1) of Eu3+ ions (590 nm). Thermoluminescence (TL) characteristics of gamma-rayed Mg2SiO4: Eu3+ phosphors are studied. Two prominent and well-resolved TL glows with peaks at 202 degrees C and 345 degrees C besides a shoulder with peak at similar to 240 degrees C are observed. The trapping parameters-activation energy (E), order of kinetics (b) and frequency factor (s) are calculated using glow curve shape method and the results obtained are discussed. (C) 2011 Elsevier B.V. All rights reserved

100MeV Si8+ Ion Induced Luminescence and Thermoluminescence of Nanocrystalline Mg2SiO4:Eu3+

Nanoparticles of Mg2SiO4:Eu3+ have been prepared by the solution combustion technique and the grain size estimated by PXRD is found to be in the range 40-50 nm. Ionoluminescence (IL) studies of Mg2SiO4:Eu3+ pellets bombarded with 100 MeV Si8+ ions with fluences in the range 1.124-22.48×1012 ions cm−2 are carried out at IUAC, New Delhi, India. Five prominent IL bands with peaks at 580 nm, 590 nm, 612 nm, 655 nm and 705 nm are recorded. These characteristic emissions are attributed to the luminescence centers activated by Eu3+ cations. It is found that IL intensity decreases rapidly in the beginning. Later on, the intensity decreases slowly with further increase of ion fluence. The reduction in the ionoluminescence intensity with increase of ion fluence might be attributed to degradation of Si-O (ν3) and Si-O (2ν3) bonds present on the surface of the sample. The red emission with peak at 612 nm is due to characteristic emission of 5D0→7F2 of the Eu3+ cations. Thermoluminescence (TL) studies of Mg2SiO4:Eu3+ pellets bombarded with 100 MeV Si8+ cations with fluences in the range 5×1011 ions cm−2 to 5×1013 ions cm−2 are made at RT. Two prominent and well resolved TL glows with peaks at ∼220 °C and ∼370 °C are observed. It is observed that TL intensity increases with increase of ion fluence. This might be due to creation of new traps during swift heavy ion irradiation.

Effect of Ageing on Shape Memory Effect and Transformation Temperature on Cu-Al-Be Shape Memory Alloy

AbstractCu-Al-Be ternary alloy are prepared by ingot metallurgy route. Thermal ageing of Cu-Al-Be shape Memory Alloy at different temperatures are carried out at various temperatures. The influence of ageing at a temperature above Af (Austenite phase finish temperature) was studied and time dependency of variation in the transformation temperature were determined. The formation of precipitates and their effects on the microstructure was studied by using OM, DSC and hardness measurements. The formation of precipitates varies the chemical composition of the alloys and thereby changes the shape memory Effect and Transformation temperature of the alloys. The investigation results are expected to benefit the applications of Cu-Al-Be SMA under different thermal conditions as a replacement of costly NiTinols

Behaviour of order of reaction and toughness of polypropylene at artificial thermal condition

Polypropylene is accumulated in the environment that serious cause for society and human. It’s degradation under artificial climate was studied in this research. Polypropylene pieces (3*15cm ) were weighted and they were kept under artificial thermal condition for 0-12 hours at 80,100,120,140˚C temperature and weight were recorded at different time interval. Average weight loss of polypropylene samples were 0.3 – 0.4 % at end of 12 hours. The order of reaction (n) varies was obtained respect to degradation of polypropylene. The toughness of material was recorded, it varied from 35% to 95% from initial values

Farmers’ Perspective about Organic Manure Production and Utilization in Dakshina Kannada, India.

The perception and utilization of organic manure have all along been critical, due to the socioeconomic and demographic factors among farmers of  different parts of the world including India. A study aimed to explore factors affecting farmer’s perception about organic manure production and its  utilization in Dakshina Kannada. A questionnaire-based survey was used to collect data from farmers and bears quantitative data. This data shows that the 3.2% of farmers adopted farming activities for more than 30 years, and the experience acquired has influenced the knowledge and perceptions on utilization of organic manure. It was found that 86% of males and females positively enjoyed producing organic manure, while 14% had a negative attitude towards the practice. The core factor influencing farmers to produce organic manure from municipal solid wastes was high yield/crop production which accounted for 16.1% of all respondents. The study indicates that the attitude and willingness to use organic manure from organic waste were high among the farmers of Dakshina Kannada, India. Therefore, an approach that can get the farmers involved in organic manure production using organic wastes could be implemented to inform good practices. Keywords: Wastes, agriculture, attitude, fertilizer, wastes management, small farmer

Tribological Aspects of Graphene-Aluminum Nanocomposites

Graphene is a new class of material in carbon group with strong sp2—hybridized 2D-sheet like nanomaterial. In order to make an effective utilization of their astounding properties, they are currently used in the form of reinforcements in various proportions in metals and its alloys to fabricate the nanocomposites. Graphene is incorporated in oil and grease at nano range that results in higher load-carrying capacity compared with that of raw grease and oils without additives, which shows that graphene possesses self-lubricating capacity. Graphene is a planar sheet-like structure (2D), with more contact surface area in the developed composites that can make them suitable for industrial applications with well-established tribological performance. The novelty of this work focuses on the role of graphene addition in enhancing the wear performance aluminum composites to replace the conventional materials by graphene composite combinations. The current chapter explains the processing and tribological performance of graphene-aluminum composites and its effect with various hybrid combinations of MWCNT/SiC/Al2O3. Dispersion of graphene is carried out through ultrasonic liquid processor followed by ball-milling aluminum powder. Thus prepared precursors are vacuum-pressed and microwave-sintered. Graphene in the nanocomposites has resulted in significantly improving the tribological properties, where it gives the wear resistance by creating a solid, lubricant layer between the sliding surfaces