Key Engineering Materials Vols. 675-676

Abstract: The measurement of erythrocyte size was studied by using diffraction technique base on laser. The light from a diode laser was observed with 650 nm and 532 nm of light wavelength through erythrocyte on the slide. The result found that the ring was appeared on the screen alternate with brightness and dark. The first brightness radius was measured on the screen (Y) and the distance of the position of the slide erythrocytes to screen (X) was observed then calculated the diameter of an erythrocyte (d) in microns (μm). The above number were calculated the volume of erythrocyte and compared with automatically complete blood count (CBC) machine by the mean corpuscular volume (MCV) with femtolitre (fl) values​ in the range 60-100 femtolitre. In conclusion, this study showed that the sizes of erythrocyte by laser diffraction technique are similar with the automated blood count. Therefore, it can be applied to measure erythrocyte size.

Abstract: The construction of an experimental set for measurement of refractive index of liquids using fiber optics has been described in this work. The experimental set is aimed for demonstration in physics high school class. A prototype fabricated in laboratory composes of plastic-clad-plastic (PCP) optical fiber with the length of 50 cm, fiber optic transmitter diode, fiber optic phototransistor detector, and liquid container. The diameter and refractive index of the core of PCP optical fiber were 1 mm and 1.492, respectively. The thickness and refractive index of fiber cladding were 1.2 mm and 1.417, respectively. The fiber cladding surface at the central region was removed approximately 5 cm long to form a sensor area. This sensor area was inserted into a cylindrical glass which acted as the container. One end of the fiber was connected to the transmitter diode with a wavelength of 660 nm, and the other end was connected to the detector. A digital multimeter was used to measure an output voltage from the detector. In this work, the effect of water temperature on its refractive index was determined. The results showed that the water refractive index decreased with increasing water temperature and result in the increase of measured output voltage. Furthermore, it was found that the output voltage measured at different temperatures of water depends linearly on water refractive index.

Abstract: A scattered photons spectrum from Compton effect were observed by pulse-height distribution of a NaI(Tl) scintillation detector. This also results in extraction of intensity distribution of multiply scattered events originating from interactions of 662 keV photons with both targets of copper sizes. The observed pulse-height distributions are a combination of singly and multiply scattered events in same photopeak. To evaluate the contribution of multiply scattered events, the spectrum of singly scattered events used reconstructed analytically. The results show that the lowest multiply scattered events occur at scattering angle 90 degree.

Abstract: In this work, the total mass attenuation coefficient and partial interactions of the zirconium alloy have been calculated by WinXCom program at 1 keV-100 MeV gamma ray energies. Zr₂(Fe,Ni) alloys was studied for the mass attenuation coefficients, photoelectric absorption, incoherent, coherent and pair production processes. The effective atomic numbers and electron densities were also calculated. The calculated results show that the total mass attenuation coefficient decreased with increasing of gamma rays energy. The value of total mass attenuation coefficient of each material was different, which depend on chemical compositions of alloy. The partials interactions, effective atomic numbers and electron densities were also calculated and discussed.

Abstract: This paper presents the investigated variations in insulation resistances of amorphous silicon (a-Si), multi crystalline silicon (MC-Si) and hybrid solar cell (HIT). The insulation resistance of PV string of each system was measured and used to represent leakage current in photovoltaic system and the analysis was done in accordance with IEC 61215 Standard. The 10.152 kW multi-PV cell technologies grid connected system supports the energy demand of the 10 kW Building at School of Renewable Energy Technology (SERT), Naresuan University since July 2005 till date. In general the system was found effectively working under hot and humid climatic conditions of Thailand for a long duration. However the decrement in insulation resistance (MΩ) of a-Si string, MC-Si string and HIT string have affected electrical parameter of each system. The decrements in fill factor (F.F) over the 10 years period (July 13, 2005 – January 25, 2015) of a-Si, MC-Si and HIT were-27.4%, -21.9% and-6.2% respectively.

Abstract: Improvement of adhesion between epoxy based post and composite resin core materials by low temperature plasma is an on-going dental material development. To systematically investigate the effects of surface change on the material’s chemical and mechanical properties, three series of two component materials, epoxy/urethane dimethacrylate (UDMA), epoxy/polyethylene (PE), and epoxy/poly(methylmethacrylate) (PMMA), were compared with dental epoxy based post/composite resin core. Each dual-materials system was modeled at an atomistic level. A molecular dynamics (MD) method with COMPASS force field was employed to simulate the most probable functionalization and the materials physical properties changes. Material surface modification was modeled and optimized using quantum calculations based on experimental characterization. To validate calculation results, the effect of plasma treatment on the mechanical properties of the dental post materials were examined by tensile pull out test.

Abstract: Atmospheric pressure plasma is potential to inhibit microbial growth on various food surfaces without affecting product bulk and leave no significant chemical residues. The aim of this work was to study the effect of atmospheric pressure argon plasma on the mold growth on white flour wheat bread and whole wheat bread. Aspergillus sp., was isolated from the two breads and inoculated on potato dextrose agar (PDA) and was directly exposed to argon plasma jet treatment at powers of 10, 20, or 40W for 5 or 10 min. Fungal dry weight determination was used to study the effect of APJ on the inactivation of the molds on the breads. The results showed there is a correlation between power level and treatment time. The higher the power and the longer the treatment time, the higher the degree of fungal inactivation. The amounts of the molds were significantly reduced after plasma treatment, especially in power of 40 W for 10 min. These results demonstrated that argon plasma jet could be used effectively to inhibit the fungal growth on bread surface.

Abstract: The civil structures of nuclear plants need to meet the most strict criteria in terms of safety and reliability not only during their design and construction, but during the duration of their life cycle. In addition, during the life-cycle of nuclear plant higher safety demands than the ones at the time of plant design may appear and the plant needs to prove meeting of such requirements. Validation of thermo-mechanical properties was required for the concrete structure of the containment building of Bohunice NPP in Slovakia. Identification of thermo-mechanical parameters of the material used in the containment structure was necessary to perform said analysis and detailed investigation on the concrete composition was performed. This paper describes the information that can be obtained using state-of-the art analytical methods – X-ray diffraction (XRD), X-ray fluorescence (XRF) and thermic analysis (TG/DTA).

Abstract: Commercial window added with BaSO₄ have been studies on the mass attenuation coefficient and compared it with some standard shielding concretes. This parameter has been investigated at photon energy from 1 keV to 100 GeV on the basis of calculation. The theoretical values of photon interaction were obtained by the WinXCom program. The variations of mass attenuation coefficient of commercial window and standard shielding concretes are shown graphically with photon energy. It has been observed that the commercial window added with 30% BaSO₄ has higher value of mass attenuation coefficient than all of standard shielding concretes at the photon energy range above 40-400 keV. Also, discontinuous jump of mass attenuation coefficient at the lower energy has been discusses.

Abstract: Inorganic scintillators of CsI(Tl), LYSO and BGO crystals were characterized using photomultiplier tube R1306 PMT readout for gamma ray detection. The photoelectron yield, light yield and photofraction were measured at gamma energies in range 59.5 keV to 1332 keV. It is found that the photoelectron yield of LYSO is much better than that of CsI(Tl) and BGO crystals. CsI(Tl) crystal showed the high light yield of 63855.25 ph/MeV in this energy range, which is better than that of LYSO and BGO crystals. The photofraction for all crystals was determined and compared with the cross-section ratio for the photoelectric effect to the total one which calculated by WinXCom program.