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Jolanun B.,Rajamangala University of Technology at Lanna | Towprayoon S.,King Mongkut's University of Technology Thonburi
Bioresource Technology | Year: 2010

New granular material from clay residue was investigated as a bulking agent for food waste composting. Five mixing ratios of granule were conducted in a laboratory scale reactor at the desired low rate of air (0.05 l min-1). The evolution of temperature and the accumulative CO2 emissions were monitored. Physical and chemical changes, N loss, and organic matter degradation of compost were also examined. Adoption of granules of 15% V/V (FAS 31.6%) enhanced the thermophilic composting and CO2 emissions; thus satisfying the Process to Further Reduce Pathogens (PFRP, USEPA) as well as obtaining the highest rate constant of organic matter degradation (k = 0.005 day-1). As the amount of granules was doubled (35% V/V), the temperature was not only cooled, but also promoted the substantial N loss (54%). It was suggested that bulking agent from clay residue can be used beneficially as reusable media for microbial inoculation as analyzed by SEM. © 2010 Elsevier Ltd. All rights reserved.

Panomwan Na Ayuthaya R.,King Mongkut's University of Technology Thonburi | Namprakai P.,King Mongkut's University of Technology Thonburi | Ampun W.,Rajamangala University of Technology at Lanna
Renewable Energy | Year: 2013

This article presented an indoor experiment on developing a mathematical model for predicting the productivity of an ethanol solar still of basin type. The test still contained a horizontal evaporating surface and a condensing surface inclined 14° to a horizontal. Various concentrations of ethanol-water solution were employed for this experiment. The distillation temperature range included boiling point. The collected data were used to estimate the mass-transfer coefficient and mass transfer conductance of the solar still. Accordingly, a mathematical model was developed based on the Spalding theory of convection and the Fick's law of diffusion. In order to increase the performance at the outdoor conditions, a basin solar still was integrated with a set of fin-plate fitting in the still basin for distillation of a 10%v/v alcohol solution. It was found that the productivity of the modified solar still was increased by 15.5%, compared to that of a conventional still. Moreover, the predicted still efficiency by the model could increase to 46% when a number of fins that raised an effective absorptance were increased. Condition of high concentration output and high productivity was investigated. Monthly mean productivity and efficiency of the still were found to increase with daily mean insolation. © 2012 Elsevier Ltd.

Chunkag V.,King Mongkut's University of Technology Bangkok | Kamnarn U.,Rajamangala University of Technology at Lanna
IET Power Electronics | Year: 2010

The analysis and design of a paralleling three-phase ac to dc converter using CUK rectifier modules for DC Distributed Power System (DPS) applications are presented. The proposed control technique is used to obtain the three-inductor current compensators and to improve the dynamic response of the rectifier without affecting its steady-state performance and also to minimize total harmonic distortion (THDi) in the source current. As a result, the output voltage of the converter can withstand the variations of the dc load current and input voltage. The control method is employed in the voltage feedback loop. The implementation of this control circuit uses only analog circuitry. The experimental prototype has been built with a DC output voltage -48 V and output power 1.5 kW. Each converter operates in Continuous Conduction Mode together with hysteresis current control. The experimental results indicate that such scheme is effective and offers the good dynamic transient response. The results obtained are: power factor higher than 0.99 and THDi less than 3%. The system offers 88% efficiency and provides good inductor current sharing among the converter modules. The simulation and experimental results are presented to verify the feasibility of the control strategy. © 2010 © The Institution of Engineering and Technology.

Chaiwong K.,Chiang Mai University | Kiatsiriroat T.,Chiang Mai University | Vorayos N.,Chiang Mai University | Thararax C.,Rajamangala University of Technology at Lanna
Biomass and Bioenergy | Year: 2013

This study examined bio-oil and bio-char fuel produced from Spirulina Sp. by slow pyrolysis. A thermogravimetric analyser (TGA) was used to investigate the pyrolytic characteristics and essential components of algae. It was found that the temperature for the maximum degradation, 322°C, is lower than that of other biomass. With our fixed-bed reactor, 125g of dried Spirulina Sp. algae was fed under a nitrogen atmosphere until the temperature reached a set temperature between 450 and 600°C. It was found that the suitable temperature to obtain bio-char and bio-oil were at approximately 500 and 550°C respectively. The bio-oil components were identified by a gas chromatography/mass spectrometry (GC-MS). The saturated functional carbon of the bio-oil was in a range of heavy naphtha, kerosene and diesel oil. The energy consumption ratio (ECR) of bio-oil and bio-char was calculated, and the net energy output was positive. The ECR had an average value of 0.49. © 2013 Elsevier Ltd.

Intra P.,Rajamangala University of Technology at Lanna | Tippayawong N.,Chiang Mai University
Aerosol and Air Quality Research | Year: 2011

Charging of nanoparticles is an important process in aerosol sizing. A unipolar charger is one of the most important upstream components in aerosol particle sizing and measurement systems by electrical mobility analysis. The aim of particle charging for an electrical mobility analyzer is to impose a known net charge distribution on the aerosol particles for each size. Charger performance depends on the extrinsic charging efficiency and stable operation. A well-designed unipolar charger should provide high extrinsic charging efficiency and stability that can be accurately determined for any given operating conditions. Depending on the mechanisms used to generate the ionized gas, the chargers can be classified into: (i) a corona discharge chargers, (ii) a radioactive chargers, and (iii) a photoelectric chargers. In this article, a brief overview on the development of existing unipolar aerosol chargers for nanoparticles is presented. Descriptions of the operating principles as well as detailed physical characteristics of these chargers, including the corona discharge, ionizing radiation, and photoelectron emission, are given. © Taiwan Association for Aerosol Research.

Intra P.,Rajamangala University of Technology at Lanna | Tippayawong N.,Chiang Mai University
Journal of Electrostatics | Year: 2010

In this study, the corona-needle ionizer was designed, constructed, and characterized. Experimental characterizations of the electrostatic discharge in terms of current-voltage relationships of the corona ionizer, including the effects of discharge electrode cone angle and air flow rate were presented. It was found that the charging current and ion concentration in the charging zone increased monotonically with corona voltage. Conversely, discharge currents decreased with increasing angle of the needle cone. The negative corona was found to have higher current than the positive corona. At higher air flow rates, the ion current and concentration were found to be relatively high for the same corona voltage. The effect of air flow rate was more pronounced than the corona voltage. It was also shown that the ion penetration through the ionizer decreased with increasing corona voltage, and increased with increasing air flow rate. The highest ion penetration through the ionizer of the 10° needle cone angle was found to be about 93.7 and 7.7% for positive and negative coronas, respectively. The highest ion penetration for the needle cone angle of 20° was found to be 96.6 and 6.1% for positive and negative coronas, respectively. © 2010 Elsevier B.V.

Mettripun N.,Rajamangala University of Technology at Lanna
2016 13th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, ECTI-CON 2016 | Year: 2016

In this paper, we present a robust medical image watermarking based on discrete wavelet transform which embed a patient's name and ID number in a medical image with in an invisible manner. The watermark is available to the respective physician only on extraction with a secret key. Principally, the blue component of original host image is decomposed by the 2-D Discrete Wavelet Transform level-2 and the watermark image is decomposed by 2-D Discrete Wavelet Transform level-1. Then, the coefficients of watermark bits in LL subband-level-1 are embedded in the coefficients of the host image in HH sub-band-level-2. The experimental results showed the improvements in term of NC of the extracted watermark and the robustness of the embedded watermark, compared to the previous methods in [10] and [12]. © 2016 IEEE.

Sriudom Y.,Rajamangala University of Technology at Lanna
Energy Procedia | Year: 2011

Salt production by evaporation of brine drawn from deep wells in of Bo Kluea District, Nan, has been carried out for many centuries by using traditional wood-based stoves. This study aims to improve thermal efficiency of traditional stoves, while tradition stove structures and salt making methods were maintained. The prototype and tradition stove were compared by thermal efficiency method. The tradition stove was constructed with clay. The prototype chimney stoves have been making from brick plastered with cement. The prototype chimney stove was insulated by filling rich hush in the gap of stove wall which has 3 cm. thicknesses and the end of the chimney. The stove can put 2 pans. Eucalyptus woods were used be fuel for testing the thermal efficiency. The prototype stove increases thermal efficiency approximately by 5.3 percents form normally 9.6 percents. This is achieved by using carbonized rice husk as stove insulating materials to reduce heat loss through stove walls. Salt production cycles are decreased by 25 minutes from 4.5-5 hours and the rate of fuel per day decreased 14-15 kilograms from 257 kg of firewood. Costs to improve salt production stoves 1,545 THB have a Pay-back period 107 days. The improved prototype chimney stove can help to decrease fuel costs and increase the salt production rate. This research is not only saving energy but also keep tradition of local living. © 2011 Published by Elsevier Ltd.

Ponglangka W.,Rajamangala University of Technology at Lanna
ICCAS 2015 - 2015 15th International Conference on Control, Automation and Systems, Proceedings | Year: 2015

The principle of the electrical capacitance properties to measure paddy rice moisture content is presented in this paper. The aim of this research is to design a low-cost paddy rice moisture content meter. Paddy rice was packed in a 600 cm3 cylindrical plastic container with the diameter of 9 centimeters and the length of 10 centimeters. The integrated circuit ICL8038 was applied to generate the frequency signal. After that, the capacitor in ICL8038 circuit was replaced by the cylindrical plastic container. Paddy rice capacitance was computed and applied to model the moisture content equation by using the second-order polynomial regression. The microcontroller (ATmega1280) was applied to calculate the moisture content and the calculation was demonstrated on 20 × 4 LCD display. Weight of each sample of paddy rice was 354 grams. The results of moisture content equation evaluated were 97.91% accurate. The examination results showed paddy rice moisture content was 97.83% accurate. The moisture content measurement range was 6% to 22% wet basis. © 2015 Institute of Control, Robotics and Systems - ICROS.

Intra P.,Rajamangala University of Technology at Lanna
Journal of Electrostatics | Year: 2012

A cylindrical triode charger for unipolar diffusion charging of aerosol particles was designed, constructed, and evaluated. The corona discharge characteristics were studied in this cylindrical triode charger. For the process the current-voltage characteristics were determined, as were the ion number concentration, the n it product, and the mean charge per particle as a function of particle diameter. The discharge and charging currents, and ion number concentration in the charging zone of the charger increased monotonically with corona voltage. The negative corona had a higher current than the positive corona. At the same corona voltage, the ion number concentration in the discharge zone was larger than the charging current for positive and negative coronas, with values of about 197 and 32 times and 645 and 99 times for the ion-driving voltages of 0 and 310V, respectively. The average ion penetration for positive and negative coronas was 0.64 and 0.19% and 3.62 and 1.93% for the ion-driving voltages of 0V and 310V, respectively. The higher flow rate, shorter residence time, gave a lower N it product. By calculation 14% of charged particles of 10nm in diameter were lost to the outer cylinder because of the electrostatic field effect. The charger does not use a sheath of air flow along the walls or the perforated screen opening, it has low diffusion and space charge losses due to the short column charging zone, and is a low complexity and inexpensive system. It worked as well as more sophisticated and expensive commercially available chargers. © 2011 Elsevier B.V.

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