http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/5680 Mon, 06 Apr 2026 14:05:07 GMT 2026-04-06T14:05:07Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1479 Sintering properties and development of ternary ZnAl2O3 phase in Al2O3 - ZnO composite ceramics Sriyananda, I.B.P.B.; Thanihaichelvan, M. Zinc doped aluminium oxide (ZnAl2O3) is a wide bandgap semiconducting material with optical transparency. The wideband gap of 3.6 eV makes it as an interesting material in several applications like gas and chemical sensors and photovoltaic devices [1]. In this work, we studied the sintering properties of the alumina (Al2O3) and zinc oxide (ZnO) composite ceramics. The Al2O3 based ceramic matrix nanocomposite reinforced by 5 mol.%, 10 mol.%, 15 mol.% of zinc oxide (ZnO) nanoparticles, has been prepared and consolidated by pressureless sintering method. Nearly fully dense composite could be obtained by sintering at 900°C for 2 h. X-ray diffraction (XRD) has been used to characterize the as-prepared and sintered powders. X-ray diffraction results revealed that the samples were crystalline with a hexagonal wurtzite phase. As the concentration of alumina (Al2O3) increases in ZnO, the X-ray diffraction peaks shifts towards higher angle. This shifting in peak position and decrease in intensity reflect that Al is successfully replaced Al in ZnO matrix and the formation of ZnAl2O3. Previous studies have reported the formation of the ternary ZnAl2O3 phase at sintering temperature 1200°C and above. However, the phase development was observed at relatively lower temperature of 900°C in this study. Further studies could pave the way to the fabrication of ZnAl2O3 composite at low cost for several applications. Fri, 01 Jan 2021 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1479 2021-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1474 Suitable shielding material for external beam therapy Dissanayake, D. M. B. Y.; Pathmathas, T.; Ramalingam, A. In radiological procedures radiation shielding apparel must protect the patients and medical personnel from unnecessary exposures. Primarily conventional radiation shielding apparel is constructed from lead impregnated sheet materials that have issues with lead toxicity, user inconvenience and are a source of environmental pollution. This research was carried out to find a suitable material for constructing shielding apparel used in high energy photon beams. In this study, for the primary photon beam of energy 6 MV, effective linear attenuation coefficients of terry cotton fabrics coated with 4.5 g/cm3 density barium sulphate (BaSO4), 4.29 g/cm3 density barium carbonate (BaCO3) and 3.86 g/cm3 density barium chloride (BaCl2) produced by impregnation and coating method, and kept between compressible frames were estimated [1]. The first step of the radiological measurements revealed that BaSO4 significantly more attenuated than BaCO3 and BaCl2, and the calculated values of the effective linear attenuation coefficient of combined terry cotton fabric and BaSO4 were 3.66 m-1 and 5.21 m-1 for 10 cm × 10 cm and 5 cm × 5 cm field size, respectively. It was concluded that the Barium Sulphate (BaSO4) coated terry cotton fabric used in this study could be utilized in the production of lab coats and other protective apparels for personnel who are routinely exposed to radioactive settings. Fri, 01 Jan 2021 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1474 2021-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1473 Sound level measurement and the setback distance of the wind turbine Rajapaksha, M.P.D.S.; Thevakaran, A. Harnessing energy from the wind is the sustainable alternative method to produce electricity. However, while having positive environmental impacts such as reduced carbon emission, environmental pollution, and water consumption; they are having considerable noise pollution and negative impact on wildlife [1]. This study examines the sound level production at the upwind and downwind of the wind turbine and estimates setback distance which is the minimum distance between the receptor and closest wind turbine. This study will help to find the minimum distance to install the wind turbine in Sri Lanka while planning and review process of wind energy projects to protect human health and avoid unnecessary confrontation by the public. In this study, the sound level measurement was done repeatedly for ten days at the upwind and downwind of three wind turbines located at Palai area in Sri Lanka. It is found that the sound level reduced drastically from 85 dB to 60 dB at the setback distance of 400 m. The result shows that the sound level produced at the upwind is 3 dB greater than the sound level at the downwind. The noise could be louder in the proximity of the turbine and cause a noise nuisance to humans. Though the measured turbine is said to create a noise of 100 dB, the sound level was estimated as 60 dB beyond 400 m of the turbine, the psychological disturbances associated with such consistent noise can be significant within this limit. Fri, 01 Jan 2021 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1473 2021-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1472 Smart cap as an electronic travel aid for visually impaired person Premadasa, D. K. M. S. A.; Dissanayaka, D. M. A. S.; Wimalarathne, A. W. G. N. M.; Hemachandra, W. G. S. M.; Gunawardhane, W. A. T. N.; Kodikara, M. M. P. S.; Loheeswaran, S. This research aimed to develop an ultrasonic sensor based smart cap as an electronic travel aid to improve the safe self-movement of the visually impaired persons. This smart cap provides the audible and mechanical vibration guidelines to the visually impaired, about the obstacles in their surroundings. Three ultrasonic sensors are connected in front, left and right sides of the cap to detect the obstacles. A buzzer and two vibration motors are connected to the cap to provide audible beep and mechanical vibrations that can be sensed by the person. All components are interfaced with Arduino UNO microcontroller and powered with 9V battery. The obstacle distance distances are set to 80 cm for front and 60 cm for left and right sides. Additionally, temperature sensor and LED display are also connected with the microcontroller to measure and display the body temperature of the person. Fri, 01 Jan 2021 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1472 2021-01-01T00:00:00Z