Advanced Materials Research Vol. 979

Abstract: Plasma is a one of state of matter that is produced by applying energy into gas or fluid like, where the ionized electrons from gas or fluid atoms to be free electrons. In this paper, the use of micro plasma source generation by using a PANDA ring resonator is introduced, in which the whispering gallery modes (WGMs) are formed within the center ring and can be used to create the high power of electromagnetic wave for gas plasma production. In application, the micro plasma source can be fabricated in small scale material process or others suitable operation. In this case, the plasma source can be decreased to be micro-scale device, where in fact, the common plasma source system size is large because the high energy source to produce high power plasma is required. Finally, the detail of using such small scale plasma source is discussed. The theoretical details of whispering gallery mode and quantum tunneling effects are also reviewed and discussed.

Abstract: This research aims to calculate the transmittance to direct irradiance due to absorption by precipitable water vapor in the atmosphere of Thailand, estimation of the absorptance by water vapor in the atmosphere and calculate the precipitable water vapor in the atmosphere. The precipitable water vapor in the atmosphere was calculated from upper air checking data relative humidity and temperature. The data were collected at four meteorological monitoring station located in Chiang Mai, Ubon Ratchathani, Bangkok and Songkhla during the years 1991-2010. The figures for precipitable water vapor obtained from this investigation were used to formulate a mathematical model relating to the precipitable water from four stations with surface climatological data, relative humidity and temperature at the same stations. The result showed that the relationship has a relatively high level of reliability. The precipitable water vapor obtained from upper air nearly is equal to the value from the model. The difference in the Root Mean Square Error (RMSE) is equal to 0.250 cm. Then, the researcher used a model to calculate the amount of precipitable water vapor at 85 meteorology stations nationwide. The result showed that the precipitable water vapor was less in the dry (November to March) and relative high in the rainy season (April-October). The average per year was found to be 4.559 cm. When analyzing the solar radiation absorption by water vapor in the atmosphere, found that the absorption is more or less depending on the precipitable water vapor in the atmosphere, which has an average annual as 15.53 percent. The transmittance to direct irradiance due to absorption average per year was found to be 84.51 percent.

Abstract: Pineapple was dried using a mix mode solar dryer developed in the Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakhon Pathom, Thailand. The dryer was designed for small-scale commercial producers of agricultural products in non-electrified locations. The products to be dried are placed in multilayer on a wire mesh in the drying tunnel to receive energy from both hot air supplied from the collector and incident solar radiation on products. It is constructed in local materials then tested experimentally in food stuffs drying pineapple. With this dryer, 40 kg of pineapple can be dried within 4 days. The dryer reduces drying losses as compared to sun drying and show lower operational costs than the artificial drying. Temperatures in the drying chamber varied from 28.0 °C to 57.0 °C depend on the weather conditions. The dryer could be used for pineapple of 83% (w.b.) moisture content, and they could be dried within 4 days, with 15% (w.b.) remaining moister. In addition, pineapples being dried in the solar tunnel dryer were completely protected from rain, insects and dust, and the dried.

Abstract: We propose a new device for detection of pesticide residues in vegetables and fruits using piezoelectric crystal biosensors. Piezoelectric crystal biosensors are based on the relationship between the resonance frequency of an oscillating piezoelectric crystal and the mass deposited on the crystal surface, which was well established by Sauerbrey. For the piezoelectric crystals vibrating in resonance frequency of the crystal is linearly related to the mass change on the crystal surface. In this project we used quartz crystal piezoelectric as a probe to detect pesticides in vegetables and fruits in Sakon nakhon province then compare it with the standard of toxins that are harmless to humans.

Abstract: The physical parameters study of contact binary system AY Aquarius, the observations were done in 12^th September 2011 at The Cerro Tololo Inter-American Observatory (CTIO), Chile. The Prompt4 0.4 - meter Ritchey-Chretien reflecting telescope and CCD Apogee Alta 10241024 pixels with standard visual and red filters of UBV were used. The orbital period of the contact binary system is about 0.28199 days. The photometry was analyzed by MaxIm program and used Wilson-Devinney technique to calculate the physical properties.

Abstract: This study adopts the Monte Carlo method to analyze the neutron flux measurement technique in Thai Research Reactor-1/Modification 1(TRR-1/M1) by performing simulations using MCNPX computer program. The neutron flux measurement technique being analyzed is called “gold foil activation technique”. The simulation model consists of gold foil located in the middle of in-core irradiation which is in the center of the reactor core. The variation in the calculated neutron flux is assessed by varying the gold foil thickness from approximately 500 – 800 μcm. It is found from the simulation that the calculated neutron flux can differ by 33 % when increasing the gold foil thickness by 60%. In addition, more detailed simulations to determine neutron flux distribution within the gold foil are performed to study and explain the variation in neutron flux calculated at different foil thicknesses. The simulation result shows that self-shielding effect has significant impact to the neutron flux distribution within the gold foil, and hence to the average neutron flux.

Abstract: In this research, we present a fabrication of an electric generation experimental kit which is comprised of pineapple peel residue from agricultural industries. Juice from squeezing pineapple peel was used as electrolyte of a galvanic cell. Sufficient acidity of the juice could activate electrochemical reaction in the galvanic cell kit using a zinc plate and copper plate as electrodes. During the experiment, adjustable distances between the two electrodes were controlled to obtain maximum output voltage. It has been already known that a galvanic cell with a lower distance between electrodes could provide higher output voltage but both electrodes could not touch each other. Experimental results from controlling distances between the 2 electrodes showed that the galvanic cell kit could provide high output voltage of 1.00 V which was able to apply in electronic devices.

Abstract: We rigorously investigate the refractive index by using the technique of the Green’s function. The propagator model of the polarization-free photon is created in quantum field theory viewpoint. The Green’s function is solved in detail with appropriate boundary originating an idea of amplitudes to propagate from place to place found in Richard Feynman's QED: The Strange Theory of Light and Matter (Princeton University Press, Princeton, New Jersey, 1985). The polarization-free photon is emitted from external sources or emitter in one medium and then propagates into another medium with the key idea: expression for amplitudes of scattering is a shrink and a tune by a certain amount, and is the same everywhere in one medium is given by determining the various contributions to probability amplitude coming from an integration over an arbitrary circular region of radius a. The purpose of this communication to establish the amplitude for the transmission of propagates by disregard about the material property. This amount is different for different materials, which corresponds to the “slowing” of the light is extra turning caused by the atoms in one medium scattering the light. The degree to which there is extra turning of the light goes through a given material is called its “index of refraction” for geometrical optics in classical physics.

Abstract: The specific activity of the natural (⁴⁰K, ²²⁶Ra and ²³²Th) and anthropogenic (¹³⁷Cs) radionuclides have been studied and evaluated for 97 surface soil samples collected from 7 districts of Phang Nga province in the south of Thailand. High-purity germanium (HPGe) detector and gamma ray spectrometry analysis system were employed to measure and analyze the experimental results. It was found that, the ranges of specific activities of ⁴⁰K, ²²⁶Ra, ²³²Th and ¹³⁷Cs in surface soil samples are 251.50 – 15740.34, 15.21 – 791.42, 18.14 – 854.34 and < 0.33 – 16.91 Bq/kg with average values are 2886.77 ± 225.93, 165.71 ± 8.45, 160.36 ± 7.93 and 5.76 ± 2.49 Bq/kg, respectively. The results were also compared with some research data in national and global radioactivity measurement and evaluations. Furthermore, the radiological hazards of Phang Nga province were calculated through the radium equivalent activity (Ra_eq), the external hazard index (H_ex), the gamma absorbed dose rate (D) and the annual effective dose rate (AED_out) and also compared with research data in the south of Thailand and the safety limits recommended values by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Moreover, the radioactive contour maps of the natural (⁴⁰K, ²²⁶Ra and ²³²Th) and anthropogenic (¹³⁷Cs) radionuclides have been also created for the investigated area.