Nunak, Navaphattra
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Nunak, Navaphattra
Alternative Name
Nunak, N.
Nunak, Navapattra
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navaphattra.nu@kmitl.ac.th
17 results
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Item type:Publication, Effect of Installation Angle of Ultrasonic Flow Meter on Water Velocity Measurement in Pipe(2017-01-01); The aim of this paper was to study the effect of installation angle of ultrasonic flow meter on the water velocity measurement in a pipe. The path angles of 45º, 55º, 65º, 75º, and 85ºwere performed in this study. The velocities were estimated by CFD techniques using the realizable k-ε model and measured by a transit time ultrasonic flow meter, and then they are compared with the results obtained from weighing method (ISO 4185). It was found that velocities estimated from CFD flow simulation at various path angles and measured from ultrasonic flow meter had a similar trend. The more difference of path angle away from the recommended specification was set, the more error of velocity measurement was obtained. The velocities at the path angles of 65ºand 85ºwere almost the same because they had an equal difference of path angle from the one that suggested in the specification. The simulated results from CFD had much error than the measured velocities of ultrasonic flow meter, especially at the long distance of path length or at a small path angle. This needed to be compensated with the correction factor. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Similarity model for estimating the error of clamp-on ultrasonic flowmeter: Flow in water supply piping system(2017-01-01); ; This study was aimed at presenting the similarity model for the estimation of error of a clamp-on, transit-time ultrasonic flow measurement. Dimensional analysis was based on the Buckingham Pi’s theorem. The groups of independent parameters that were taken into account for the analysis included pipe characteristic, fluid characteristic, and meter installation setting. Experimental testing section was fabricated using PVC pipes with diameters of 1-in and 2-in and 45º PVC elbows. Flow velocity was fixed at 0.5 m/s. The upstream and downstream distances were in the ranges of 2D-20D and 2D-10D, respectively. It was found that the upstream and downstream distances greatly affected the accuracy of the measurement. Larger relative errors were found from the measurement on the smaller pipe. With the installation of ultrasonic transducers according to the recommended value by FCI, the error obtained with the measurements on 1-in and 2-in diameter pipes were, respectively, 7% and 0.35%. The acceptable measurement ranges of upstream distance for 1-in and 2-in diameter pipes were 16D-20D and 6D-20D, respectively. The measurements on a 2-in diameter pipe with a downstream distance in a range of 4D-10D was acceptable. For the 1-in diameter pipe, any downstream distance less than 10D resulted in unacceptable error. The accuracy of measurement was more sensitive to the change of downstream distance than the change of upstream distance. The applicable range of the prototype prediction equation was greatly affected by the flow model. The equation obtained with a 1-in diameter flow model could only be used to predict a 2-in diameter prototype within a range of 18D-20D. Increasing the size a flow model could greatly broaden the applicable range the applicable range of the prediction equation. A 2-in diameter flow model could be used to predict a prototype upto 150 in. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, 3D inspection for HDD production process using laser light sectioning(2015-01-01); This research proposes the automatic visual inspection from three-dimensional characteristics of Hard Disk Drive case tightening process by machine vision system using laser light sectioning. The machine vision camera captures a number of features of HDD perpendicular to a conveyor belt as seen by a laser strip light. The narrow band pass filter (650 nm.) was mouthed in front of lens in order to cut off the unwanted wavelength. After image pre-processing, the laser profiles were calculated the center of gravity to extract the image coordinate. The features used here are the laser strip profile at various locations along the HDD formulating the 3D data. The homography computation was used to transform the image coordinate to the real world distance (in metric system). This scheme can be used to inspect the completeness of screwing process of the HDD which the 2D visual inspection cannot perform on the top view. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal image resolution on angular emissivity measurements using infrared thermography(2015-01-01); This paper reports the effect of viewing angle and thermal image resolution (IFOV and FOV) of Thermal Imager (TI) on the emissivity, with a view to providing a potential temperature monitoring of equipment in the electrical power distribution system which the reliability of system is the most important concern. The results show that the emissivity, which is the most important parameter to obtain the accurate temperature, is approximately constant at the viewing angle less than 45°. In case of the changing of the object to detector distance, this will not affect to the temperature measurement if MFOV at the object level is smaller than the targeted object. This can be concluded that TI is an effective tool to measure the temperature and monitor the failure of electrical equipment installed in the position at far away from the operator. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Similarity Model of MWA Thailand Water System for Error Estimation of Ultrasonic Flow Meter(2017-01-01); This paper proposed a similarity model of MWA water system using the dimensional analysis based on the theory of Buckingham Pi for error estimation of transit-time ultrasonic flow meter with clamp-on at different installation conditions. There were three main parameters groups, i.e., pipe characteristic, meter installation, and fluid characteristic and properties and could be arranged in five Pi terms, i.e. E×(L<inf>e</inf>/D), µ/ρvD, L<inf>e</inf>/D, U<inf>s</inf>/D and U<inf>s</inf>/D. The results showed that the relative errors of measurement increased with the decreasing of upstream and downstream of meter at the same velocity and there was a possibility to use the model to determine the correction factor to compensate the velocity measurement of ultrasonic flow meter as the installation could not comply with the requirement. However, the further experiments should be performed for validation of the model predictive equation i.e., E 0.3607 E <sup>.</sup> p m. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Detection of Foreign Bodies in Roasted Coffee by using Active Thermography(2017-01-01); This paper presents the detection of foreign bodies in roasted coffee by using active thermography with real-time thermal image processing. Foreign bodies, including stone, wood, etc., are found in roasted coffee beans contaminated during drying process and transportation. The principle of radiation from objects with different emissivity and heat capacity is applied. The heat radiation from the roasted coffee and the foreign body are different; therefore, the thermal image can be used to identify the foreign objects. The active thermography system consists of a thermal image camera and computer image processing, heat source and conveyor system controlled by programmable logic controller. The testing and experimental results of the proposed system show that the foreign bodies in roasted coffee beans can be found in all batches, however, the number counting of foreign objects are inaccurate. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Estimation of thermal conductivity and thermal diffusivity of biological materials using thermographic camera(2014-01-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The uncertainty in sugar solution concentration measurement based on density approach(2013-11-04); ; The concentration of solution used in osmotic process is an important factor to dehydrate water from food, which is an effect to the rate of mass transfer. Therefore, the in line measurement and control of the concentration in osmotic process is taken into account. The density of sugar solution can be computed by volume and weight in order to determine the concentration in degree of Brix. This instrument will complete when accompanied by a statement of its uncertainty. The calibration equation established the relationship between the reading values of sensor and the values of concentration also need to clarify. The objective of this paper is to evaluate the uncertainty of predicted values of calibration equation; therefore, the uncertainty is determined in this study, and to compare the obtained results from the classical method in linear equation and the inverse method. Furthermore, the data from Monte Carlo simulations also are compared to the measured data. © (2013) Trans Tech Publications, Switzerland. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mass-volume-area properties of frozen Skipjack tuna(2012-05-01); ; This study investigates the physical properties of Skipjack tuna (Katsuwonus pelamis), including weight, size, volume, apparent density, surface and projected area, and the correlation between these parameters. An analysis of the physical characteristics of the Skipjack tuna suggests that its shape can be broken down into three main sections: the head, the center, and the tail. The central section of Skipjack tuna can be considered a barrel shape with an elliptical cross section, whereas the head and tail can be considered cones with elliptical bases. Linear regression analyses between fish weight and other geometric properties revealed a significant correlation (R<sup>2</sup> = 0.74-0.97) to volume, projected area (side and top view), length, width (measured at the thickest part), and perimeter (measured at the thickest part). The results from this systematic analysis could be used in the design of new processes and equipment for Skipjack tuna processing. © 2012 Copyright Taylor and Francis Group, LLC. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A CFD study on wall shear stress of falling water film on food contact surface(2018-08-14)