Humidity dependence of visible absorption spectrum of gelatin films containing cobalt chloride

Otsuki, Soichi; Adachi, Kimihiro

doi:10.1002/app.1993.070480907

Cited by 19 publications

(20 citation statements)

References 21 publications

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“…Untuk sensor kelembaban optik menggunakan bahan hidrogel juga banyak dilakukan, termasuk dengan gelatin sebagai hidrogel alami. Prinsipnya, bahan hidrogel gelatin mengalami pembengkakan ketika menyerap air sehingga kerapatannya berkurang yang mengakibatkan sifat optiknya juga berubah, yaitu nilai indeks bias optiknya berkurang terhadap jumlah air yang diserap [6][7][8].…”

Section: Pendahuluanunclassified

“…Polimer seperti gelatin membengkak karena air mengisi rongga-rongga pada polimer (diameter rongga membesar), akibatnya akan mengurangi indeks bias polimer, sehingga indeks bias polimer akan mendekati indeks bias air [7]. Gelatin memiliki pori yang relatif lebih besar dibandingkan polimer-polimer sintesis [6].…”

Section: Pendahuluanunclassified

“…Perubahan sifat optik (indeks bias) polimer gelatin ketika menyerap uap air dapat dimanfaatkan sebagai material sensor kelembaban optik [7,8]. Dalam makalah ini gelatin digunakan sebagai cladding pengganti bagi serat optik untuk aplikasi probe sensor kelembaban relatif (RH).…”

Section: Pendahuluanunclassified

“…Dalam beberapa artikel, probe sensor serat optik dikembangkan dengan menggunakan cladding gelatin yang doping CoCl 2 untuk meningkatkan sensitivitas probe sensor terhadap kelembaban [ 7,8].…”

Section: Hasil Dan Pembahasanunclassified

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Pengembangan Probe Sensor Kelembaban Serat Optik Dengan Cladding Gelatin

Maddu¹,

Modjahidin²,

Sardy³

et al. 2010

MST

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AbstrakTelah dikembangkan probe sensor kelembaban menggunakan serat optik dengan cladding gelatin. Pada probe sensor kelembaban ini, cladding asli serat optik diganti dengan lapisan gelatin sebagai cladding sensitif kelembaban. Untuk menguji respon sensor serat optik yang dibuat, dilakukan pengukuran intensitas cahaya yang ditransmisikan pada probe serat optik untuk setiap variasi perlakuan kelembaban berbeda. Respon probe sensor serat optik ini diukur dari kelembaban 42% hingga 99% RH, hasilnya memperlihatkan kurva transmisi optik berbavariasi terhadap nilai kelembaban relatif (RH). Transmisi optik di dalam probe serat optik meningkat terhadap kenaikan nilai RH pada suatu rentang panjang gelombang spesifik, yaitu pada spektrum pita hijau hingga merah (500 nm -700 nm), dengan variasi signifikan pada rentang 600 nm sampai 650 nm atau dalam pita spektrum kuning hingga merah. Panjang gelombang dimana intensitas maksimum transmisi optik terjadi pada panjang gelombang 610 nm. Dengan demikian, probe sensor kelembaban serat optik ini dapat merespon kelembaban dari 42 %R hingga 99%H dengan respon terbaik pada rentang kelembaban 60%RH hingga 72%R yang memiliki linieritas dan sensitifitas yang cukup baik. AbstractDevelopment of Fiber-Optic Humidity Sensor Probe with Gelatin Cladding. Humidity sensor based on optical fiber with gelatin cladding has been developed. In this humidity sensor probe, the origin cladding of optical fiber is replaced by gelatin coating as humidity sensitive cladding. Testing of the optical fiber sensor probe was conducted by measuring of light intensity transmitted on the optical fiber probe for each variation of different humidity treatments. Response of the optical fiber sensor probe measured from 42%RH to 99%RH, the results show an optical transmission curve varied with relative humidity (RH). Optical transmission in the optical fiber probe increase with RH value at a specific wavelength range, that is from green to red spectrum bands (500 nm -700 nm), where a significant variation from 600 nm to 650 nm in yellow to red spectrum bands. Wavelength where is a maximum intensity of optical transmission occurs at 610 nm. Therefore, the optical fiber humidity sensor probe could response humidity form 42%RH to 99%RH with the best response in humidity range of 60%RH to 72%RH that is have a good linearity and sensitivity.

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Section: Pendahuluanunclassified

Section: Hasil Dan Pembahasanunclassified

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Pengembangan Probe Sensor Kelembaban Serat Optik Dengan Cladding Gelatin

Maddu¹,

Modjahidin²,

Sardy³

et al. 2010

MST

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“…Due to these disadvantages, this optical method could not practically be used to determine moisture content before development of a method and instrument for expressing color numerically. Recently, using optical fiber and color value change of CoCl2 hydrate according to humidity and temperature, fiber optic humidity and temperature sensors have been developed to detect relative humidity and temperature in air (Otsuki and Adachi 1993, Kharaz and Jones 1995, Hypszer and Wierzba 1997, Kawamura et al 1999, Dybko et al 1999, Coera et al 2000. In this study, the surface of wood was treated with CoCl2 and the color changes were measured using a spectrophotometer at various surrounding humidity conditions.…”

Section: Introductionmentioning

confidence: 99%

Moisture Distribution and Flow During Drying of Wood and Fiber

Zink-Sharp¹,

Hanna²

2001

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New understanding, theories, and techniques for moisture flow and distribution were developed in this research on wood and wood fiber.Improved understanding of the mechanisms of flake drying has been provided. Observations of flake drying and drying rate curves revealed that rate of moisture loss consisted of two falling rate periods and no constant rate drying period was observed. Convective heat transfer controls the first period, and bound water diffusion controls the second period.Influence of lower drying temperatures on bending properties of wood flakes was investigated. Drying temperature was found to have a significant influence on bending stiffness and strength.A worksheet for calculation of the energy required to dry a single strandboard flake was developed but has not been tested in an industrial setting yet.A more complete understanding of anisotropic transverse shrinkage of wood is proposed based on test results and statistical analysis. A simplified model of a wood cell's cross-section was drawn for calculating differential transverse shrinkage. The model utilizes cell wall thickness and microfibrillar packing density and orientation. In spite of some phenomena of cell wall structure not yet understood completely, the results might explain anisotropic transverse shrinkage to a major extent.Boundary layer theory was found useful for evaluating external moisture resistance during drying. Simulated moisture gradients were quire comparable to the actual gradients in dried wood. A mathematical procedure for determining diffusion and surface emission coefficients was also developed. Thermal conductivity models of wood derived from its anatomical structure were created and tested against experimental values. Model estimations provide insights into changes in heat transfer parameters during drying.Two new techniques for measuring moisture gradients created in wood during drying were developed. A new technique that utilizes optical properties of cobalt chloride was developed for nondestructive determination of surface moisture content. 2Fundamental new understanding of drying characteristics in wood and fiber has been provided that can be used by researchers to improve drying of wood and fiber. The three techniques for measuring moisture content and gradients provided in this study are efficient, practical, and economical -easy to apply by industry and researchers. An energy consumption worksheet is provided as a first step toward reducing energy consumed during drying of lumber and strandboard flakes. However, it will need additional verification and testing. COMPARISION OF ACCOMPLISHMENTS WITH OBJECTIVESObjectives of this project were to determine flow rate and direction, location, concentration, and gradient character of moisture in solid wood, OSB flakes, and wood fiber using four experimental approaches and then apply this understanding to increase the efficiency and quality of industrial drying of lumber, wafers, and wood fiber.Flow rate and direction of OSB flakes as influenced by lower drying temper...

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Resistive-type humidity sensors based on PVP-Co and PVP-I2 complexes

Queiroz

Soares

Trzesniak

et al. 2001

J. Polym. Sci. B Polym. Phys.

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Poly(vinylpyrrolidone) films containing cobalt chloride or iodine were investigated to obtain information on their possible use as a humidity sensor element. FTIR and UV‐VIS spectroscopies were used to characterize the PVP–I2 and PVP–Co complexes. Infrared spectroscopy revealed a structural change of both shape and intensity of the carbonyl and lactam bands, indicating the formation of an ion‐coordination polymer. The J–E curves for pure PVP, PVP–I2, and PVP–Co films obey ohm's law at low voltages, deviate from the linear response at higher voltages, and finally display breakdown behavior. An increase in current density of the PVP matrix with iodine or cobalt doping is attributed to the formation of charge transfer complexes. The observed hysteresis of the I–V characteristics implies that there was some standing voltage in the film, which could be attributed to a disorientation of polar side groups of PVP. The electrical conductivities of the polymeric complexes were very sensitive to environmental humidity. An explanation of the humidity‐sensing behavior of the PVP–I2 and PVP–Co complexes is presented. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 459–469, 2001

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Humidity dependence of visible absorption spectrum of gelatin films containing cobalt chloride

Cited by 19 publications

References 21 publications

Pengembangan Probe Sensor Kelembaban Serat Optik Dengan Cladding Gelatin

Pengembangan Probe Sensor Kelembaban Serat Optik Dengan Cladding Gelatin

Moisture Distribution and Flow During Drying of Wood and Fiber

Resistive-type humidity sensors based on PVP-Co and PVP-I2 complexes

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