Nunak, Navaphattra

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Nunak, Navaphattra
Alternative Name
Nunak, N.
Nunak, Navapattra
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Email
navaphattra.nu@kmitl.ac.th

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    Item type:Publication,
    Estimation of thermal conductivity and thermal diffusivity of biological materials using thermographic camera
    (2014-01-01)
    Nunak, Navaphattra
    ;
    Sritham, Eakasit
    ;
    Songthai, Maethinee
    ;
    Suesut, Taweepol
    This study proposes a method to estimate thermal conductivity and thermal diffusivity using a thermoelectric device and a thermographic camera. The experimental results were compared with others literatures. Three different materials including acrylic, apple, and potato were tested. The proposed method has proved to be effective. The experimental results for all selected materials are in comparable range with literature values. The proposed method can be a useful tool for determining thermal properties of solid biological materials with low thermal conductivity and diffusivity values.
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    Estimation of the organic film thickness on stainless steel using image intensity
    (2018-08-14)
    Songthai, Maethinee
    ;
    Suesut, Taweepol
    ;
    Nunak, Navaphattra
    This research proposes an estimation of thickness of organic film coating on a Stainless Steel surface (SS) and a clear microscope slide using a visible optical method with the image intensity level analysis. Sweetened Condensed Milk (SCM) was used as a representative of the organic film. The uncertainty of inverse calibration equations was evaluated to determine the reliability of this technique. The results showed that the image intensity increased with the increasing of the film thickness in a linear relationship with a high coefficient of determination (R<sup>2</sup> > 0.97). Uncertainty of both inverse calibration equations was low and acceptable. It could be concluded that this technique could be used to estimate the thickness of the organic translucent film coating directly on a SS or a clear slide with the limitation of approximately 1.0 mm thickness using the reported linear inverse calibration equations.
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    Investigation of soy milk deposited on stainless steel by infrared thermography
    (2018-01-01)
    Suesut, Taweepol
    ;
    Songthai, Maethinee
    ;
    Nunak, Navaphattra
    This paper proposes a real-time investigation of soy milk deposited on stainless steel surface (SS) during the heating process by considering the relationship between emissivity and mass of soils on the surface using a thermal image processing technique. The understanding on organic fouling behavior is an important step leading to the optimum cleaning operations. The mass of soy milk deposited on SS during heating process at the temperature of 75°C for 180 min was measured by the weighing method and compared to the emissivity values analyzed from the infrared thermography in real-time. Two different types of stainless steel grades (AISI 304 and 316) with various average surface roughness (R<inf>a</inf>) values (0.4, 0.8 and 3.2 µm) were carried out. Emissivity values of sample plates which soil deposited on the surface, were obtained from the real-time processing of a thermo-map of soil film compared to the temperature of a reference surface (known emissivity value). Applying this technique to all conditions, it was found that the increasing of emissivity values of sample plates as the amount of soil film on SS increased could be detected in real-time for both SS grades. The emissivity of SS having soil on the surface was higher than a clean SS since the soil film on the SS caused the roughness of surface changed. It could also detect that emissivity values of both SS grades had no significantly difference at the same R<inf>a</inf>. From the detection of soy milk deposited on SS using the real-time thermal image processing acquired from infrared camera during heating process, it could be concluded that the proposed technique was possible to investigate the accumulation of soy milk and other soil types on the surface.