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Investigation on Electron Absorbed Dose in a Mixture of Natural Rubber Latex and Cross-linking Agents

Journal of physics: Conference series 2018年第1期1144卷

作者： P Nanthanasit P Jaikaew E Kongmon s Rimjaem Plasma and Beam Physics Research Facility Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Master Degree Program in Physics Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Master Degree Program in Applied Physics Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Thailand Center of Excellence in Physics Commission on Higher Education Bangkok 10400 Thailand Research Center in Physics and Astronomy Chiang Mai University Chiang Mai 50200 Thailand

Natural rubber vulcanization using electron beam is one of interesting applications of electron accelerators with an energy in a range of a few hundred keV to a few MeV. At the Plasma and Beam physics (PBP) Research Facility, Chiang Mai University, a 4-MeV radio-frequency (RF) linear accelerator is developed for utilizing in natural rubber vulcanization. To accelerate the vulcanization process, cross-linking agents are added in a natural rubber latex to increase the bonding probability between the chains of rubber molecules. This research used a Monte Carlo based program GEANT4 to simulate the electron absorbed dose in a mixture of natural rubber latex and cross-linking agents. The initial electron energy distributions were obtained from the beam dynamic simulation in the accelerator, which were done with program AsTRA. The initial electron beams have average energy in the range of 0.70 to 4.02 MeV at the position 6 cm prior the 50μm titanium vacuum window foil. The air gap between the vacuum window to the natural rubber latex was set at 18 cm. The electron beam transportation in the titanium foil, air gap and a mixture of natural rubber latex were simulated. The cross-linking agents that are added in the natural rubber latex are ethylene glycol dimethacrylate (EDMA) and 1,6-hexanediol-diacrylate (HDDA). Finally, electron absorbed dose distributions in both transverse direction and along the depth of the natural rubber latex mixed with each cross-linking agent were calculated and analyzed. The results from this work can be used for experimental planning of electron beam irradiation on the natural rubber latex with appropriate cross-linking agents and electron absorbed dose.

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Physical and chemical characterization of Lopburi clay before and after calcination

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Journal of physics: Conference series 2019年第1期1380卷

作者： P Chomyen s sinthupinyo B Chamnankid W Hanpongpun A Chaipanich Advanced Cement-based Materials Laboratory Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Master Degree's Program in Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Research and Innovation Center SCG Cement Co. Ltd. Kaeng Khoi Saraburi 18260 Thailand Center of Excellent in Materials Science and Technology Chiang Mai University Chiang Mai 50200 Thailand

supplementary cementitous materials (sCMs) may be used as a substitution of Portland cement to reduce CO2 emissions in the cement industry. One of promising supplementary cementituous materials for practical use in the construction industry is calcined clay. Clay must be calcined to form high reaxtivity pozzolanic materials from mineral addition known as amorphous metakaolin (As2). Calcined clay may be used to improve mechanical properties, durability and some characteristic. This research aimed to study clay mineralogy and chemical composition of Lopburi clay in Thailand. Physical and chemical characterizations of Lopburi clay before and after calcination were investigated using X-Ray Diffraction, Qualitative X-Ray Diffraction (QXRD), scanning Electron Microscopy (sEM) and X-Ray Fluorescene. The results showed that Lopburi clay main major oxides aed silicon dioxide (siO2), alumina oxide (Al2O3) and iron oxide (Fe2O3) furthermore, Lopburi clay is kaolinite clay.

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Electrical properties and microstructure of phase combination in BaTiO3-based Ceramics

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Journal of physics: Conference series 2018年第1期1144卷

作者： N Funsueb A Limpichaipanit A Ngamjarurojana Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand PhD's Degree Program in Applied Physics Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand

Perovskite barium titanate (BaTiO3) ceramics are widely used in electronics industries such as capacitors, sensors and actuators. BaTiO3-based ceramics have good dielectric, ferroelectric and piezoelectric properties. BaTiO3 powder was fabricated by mixed-oxide method via a vibro-milling technique. The pellets were then placed in a high purity alumina crucible in air and sintered at 1375 °C for 1, 2, 4, 6 and 8h. X-ray diffraction technique was used to investigate phase formation of BaTiO3 ceramics. Grain size was measured by scanning electron microscopy (sEM). The computer-controlled dielectric measurement system consisted of a high precision LCR-meter. Electric field induced polarization was measured by sawyer-Tower circuit. In this work, the effect of phase combination in BaTiO3 ceramics on electrical properties (dielectric and electric field induced polarization) and microstructure was investigated.

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Evaluation of southwest Monsoon Change over Thailand by High-resolution Regional Climate Model under High RCP Emission scenario

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Journal of physics: Conference series 2018年第1期1144卷 012112-012112页

作者： Arpornrat, Theerapat Ratjiranukool, sujittra Ratjiranukool, Pakpoom sasaki, Hidekata Master’s Degree Program in Applied Physics Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai Thailand. Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai Thailand. Department of Physics Faculty of Science and Technology Chiang Mai Rajabhat University Chiang Mai Thailand. Meteorological Research Institute Tsukaba Japan.

The 5×5 km resolution of Non-Hydrostatic Regional Climate Model (NHRCM) developed by Meteorological Research Institute, Japan was used to evaluate the southwest monsoon season that affects to Thailand during mid-May until mid-October in each years. Bulk-type cloud microphysics, Kain-Fritsch convective scheme, Mellor-Yamada-Nakanishi-Niino level 3 PBL scheme, clear-sky radiation scheme and Hirai-Ohizumi land surface scheme are used as model configuration to simulate climate data under high emission scenario-RCP 8.5. This research was conducted for 2 time periods, i.e., baseline period (1981–2000) and future period (2080–2099), to estimate the southwest monsoon season onset and offset over Thailand by using average wind vector and cumulative precipitation in consecutive 5 days (pentad). Furthermore, the rain-break phase, less precipitation ranges during the southwest monsoon season, had also been analysed.

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Hydrophobicity Recovery of Polydimethylsiloxane Treated with Oxygen Plasma and Ion Implantation

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Journal of physics: Conference series 2018年第1期1144卷

作者： s Natyanun N Pussadee Master's Degree Program in Physics Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Plasma and Beam Physics Research Facility Department of Physics and Materials Science Chiang Mai University Chiang Mai 50200 Thailand Thailand Center of Excellence in Physics Commission on Higher Education 328 Si Ayutthaya Rood Bangkok 10400 Thailand.

One of a few disadvantage properties of polymethylsiloxane (PDMs) is its hydrophobicity which can hinder its fluidic applications. Oxygen plasma treatment on PDMs surfaces is a conventional method in rendering them hydrophilic, however hydrophobicity returns within days after treatment. This study proposes oxygen ion implantation at the micrometer scale inside PDMs structures to ensure lasting hydrophilicity. The PDMs slabs were treated with 20 keV oxygen ion with 1 × 1015 ions/cm2 fluence and inductively coupled oxygen plasma generated at a power of 28 W and frequency of 13.56 MHz. The chemical composition of the treated PDMs surface was monitored by X-ray photoelectron spectroscopy (XPs) and it was found that oxygen concentration remain high after three days of oxygen plasma treatment on the PDMs. Although the surface oxygen concentration in the oxygen ion implanted PDMs was not as high as that oxygen plasma treated PDMs, the oxygen concentration level was remained higher than that of the untreated PDMs surface for four weeks.

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Characterizations of carbon nanotubes grown on clay

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Journal of physics: Conference series 2019年第1期1380卷

作者： Aodkeng, s sinthupinyo, s Chamnankid, B Hanpongpun, W Chaipanich, A Advanced Cement-based Materials Laboratory Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Master Degree’s Program in Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Research and Innovation Center SCG Cement Co. Ltd. Kaeng Khoi Saraburi 18260 Thailand Advanced Cement-based Materials Laboratory Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Center of Excellent in Materials Science and Technology Chiang Mai University Chiang Mai 50200 Thailand

Carbon nanotubes (CNTs) are nano materials that have unique physical and mechanical properties. Carbon nanotubes grown on clay (Clay-CNTs) are new hybrid material based on clay mineral. Clay minerals were used as catalyst for CNTs synthesis by chemical vapor deposition at 700 °C for 1 hour. In this work, Clay-CNTs were investigated by various analytical techniques such as X-ray diffraction (XRD), scanning electron microscope (sEM) and electron diffraction spectrometer (EDs) and Raman spectroscopy to analyse the phase identification of crystalline, morphology and crystallinity quality of Clay-CNTs. Moreover, thermogravimetric analysis (TG) was studied to ident ify phase deco mposition. XRD results indicate crystallites of the CNTs have (002), (101) and kaolinite and quartz from clay mineral catalyst. sEM images of Clay-CNTs showed cluster of CNTs on carbon fiber and their wormlike morphology. The intensity of Raman spectra of Clay-CNTs reveals the defect of CNTs structure. TGA derivative profile indicated decomposition of CNTs and kaolin.

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simulations and measurements of the dipole magnet using in the 4-MeV electron spectrometer

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Journal of physics: Conference series 2018年第1期1144卷

作者： E Kongmon P Wongkummoon s Rimjaem Plasma and Beam Physics Research Facility Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Master Degree Program in Applied Physics Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Thailand Center of Excellence in Physics Commission on Higher Education Bangkok 10400 Thailand Research Center in Physics and Astronomy Chiang Mai University Chiang Mai 50200 Thailand

A dipole magnet is one of important components in particle accelerators. It can be used to transport a charged particle beam with desired deflecting angle and direction. Moreover, it is often utilized as a part of an energy spectrometer. This research focuses on simulations and measurements of the dipole magnet, which will be used to measure the electron beam energy produced from the 4-MeV radio-frequency (RF) linear accelerator (linac) for natural rubber vulcanization at the PBP-CMU Electron Linac Laboratory of the Plasma and Beam physics (PBP) Research Facility in Chiang Mai University (CMU). The research activities are divided into three main parts. The first part focuses on three-dimensional (3D) simulation of the dipole magnet by using the RADIA program. The 3D field map of the magnetic field can be derived from the RADIA model. The second past is the magnetic field measurements of the magnet after the construction. The maximum magnetic field of 248.6 mT can be obtained with an excitation current of 3 A. The last part focuses on the electron beam dynamic study by using the program called AsTRA to track the particles though the 3D magnetic field distribution. The simulation data provides six-dimensional coordinates of the particles at the considered position downstream the dipole magnet. The optimal bending angle of the 4-MeV electron beam in the magnetic field of 0.22 T is 50° with an energy spread of 0.827 MeV.

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study on Penetration of 4-MeV Electron Beam in Natural Rubber Latex

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Journal of physics: Conference series 2018年第1期1144卷

作者： K Kosaentor P Apiwattanakul s Rimjaem Plasma and Beam Physics Research Facility Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Master Degree Program in Applied Physics Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Thailand Center of Excellence in Physics Commission on Higher Education Bangkok 10400 Thailand Research Center in Physics and Astronomy Chiang Mai University Chiang Mai 50200 Thailand

Vulcanization with electron beam irradiation provides unique and high efficient processing for natural rubber latex. It is one of very interesting and effective industrial applications of particle accelerators. A radio-frequency (RF) linear accelerator (linac) and electron beam irradiation system have been developed for natural rubber vulcanization at the PBP-CMU Electron Linac Laboratory of the Plasma and Beam physics (PBP) Research Facility, Chiang Mai University (CMU). This accelerator will be able to produce electron beams with maximum energy up to about 4 MeV. In this research, we used a Monte Carlo simulation program called GEANT4 to study transportation of 4-MeV electron beam with Gaussian transverse distribution through a vacuum window, an air gap and natural rubber latex. The vacuum window is made of 50-micron titanium foil and the natural rubber was placed 18 cm downstream the foil exit. simulations of electron depth dose and transverse distribution in these media were conducted. In addition, calculation on the irradiation throughput was performed. The study results revealed that for the electron beam with Gaussian transverse distribution and an average energy of 4.06 MeV, the irradiation area should be 2.8 mm×2.8 mm with the depth of 8 mm. With this condition, the irradiation time of 0.02 second will provide the dose of at least 50 kGy per irradiated point, which is enough for the rubber vulcanization process. The overall irradiation throughput rate is 6.865 kg/hr.

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strain Distribution in Circular Disk of PMMA by Using Reflection Polariscope

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Journal of physics: Conference series 2018年第1期1144卷

作者： Y Manjit A Limpichaipanit A Ngamjarurojana Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Faculty of Science at Si Racha Kasetsart University Si Racha Campus Chon Buri 20230 Thailand PhD's Degree Program in Applied Physics Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand

The experiment was conducted to study strain distribution in circular disk of PMMA by photoelasticity in reflection polariscope. The strain in circular disk was induced by two point load created by hydraulic system (535.37-994.63 N) with the step increase of 153.21 N. We added the Babinet compensater in basic reflection polariscope to observe the fractional isochromatic fringe order in the first quadrant of disk and we calculated strain by using stressstrain optic laws. The result showed the relation between absolute of different strain in first quadrant of circular disk and the relation of force with absolute of different strain. It was found that maximum different strain produced at contact area of disk decreased along horizontal and vertical direction. The relation of force with different strain was linear.

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A study of Carteria sp. Cell Electrical Lysis in straight and Tapered Microfluidic systems

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Journal of physics: Conference series 2018年第1期1144卷

作者： P Chimsiri K Masaen J sanglao R Techapiesancharoenkij N Pussadee Master's Degree Program in Physics Faculty of Science Chiang Mai University Chiang Mai 50200 Thailand Department of Materials Engineering Faculty of Engineering Kasetsart University Bangkok 10900 Thailand Thailand Center of Excellent in Physics Commission on High Education 328 Si Ayutthaya Road Bangkok 10400 Thailand Plasma and Beam Physics Research Facility Department of Physics and Materials Science Chiang Mai University Chiang Mai 50200 Thailand

Electrical cell lysis is one of the most efficient techniques in cell analysis in extracting intracellular components for further use or examination. Cells are exposed to high electric field strength that can rupture cell membrane due to nano-size pores creation. Thanks to microfabrication technology, electrodes can be materialized in close proximity to each other leading to high electric field strength with low applied voltage. In this study, two microfluidic systems were designed: straight and tapered systems. The straight channel was chosen due to the ease of fabrication, while the tapered channel was picked since it intensifies electric field strength in the tapered area. Finite element method was used to simulate electric field distribution inside the microfluidic systems and transmembrane potential (TMP) across cell membrane. In the experiment, green algae Carteria sp. which contains large amount of lipid was used in performing microfluidic electrical cell lysis. For 30 nm thick gold planar electrodes with 110 μm spacing fabrication, the simulated TMPs produced in both microfluidic systems exceed 0.2 V which is a threshold potential for pore generation in cell membranes when applying 34 V p–p , 1000 Hz AC voltage. Only Carteria sp. cells were successfully lysed in straight microfluidic system after being exposed to high electric field strength for several minutes. Although electric field in the tapered region was higher than that of the straight microfluidic system, the cells were rushed out of the tapered region due to electrohydrodynamic effects.

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