In the construction industry, silicone is primarily used as sealant material to fill gaps and cracks providing water and air-tightness to vertical construction projects reducing energy usage bills and enhancing the in...In the construction industry, silicone is primarily used as sealant material to fill gaps and cracks providing water and air-tightness to vertical construction projects reducing energy usage bills and enhancing the integrity of construction materials. This paper reports the results of spectral analysis of commonly used building sealant materials used in residential and commercial buildings. A dozen commercially available silicone-based sealant materials composed of different ingredients representing three manufacturer brands are characterized using Raman and UV-VIS-NIR spectroscopic techniques. The characteristic vibrational fingerprints of the selected sealant materials are summarized, and the Raman and reflectance spectra of the samples are also presented. It is observed that most of the samples appear to have similar vibrational band assignments and reflectance spectra. However, analysis of the Raman spectral positions and the reflectance spectra reveals that there are distinct differences among the sealant materials.展开更多
Transmission of light through model human epidermal samples is investigated at four different wavelengths and at varying ambient humidity. Light from light emitting diodes (LEDs) is used for transmission measurements ...Transmission of light through model human epidermal samples is investigated at four different wavelengths and at varying ambient humidity. Light from light emitting diodes (LEDs) is used for transmission measurements through the samples at a UVA wavelength of 365 nm, and visible wavelengths of 460 nm, 500 nm, and 595 nm. Ambient air-humidity is varied between 20% and 100%. Results show that for high ambient humidity, near 100%, transmission of light through the epidermis is higher than at low ambient humidity, 60% or lower. These results are explained with a simple model of epidermis as a turbid medium and the effect of adsorbed water in reducing light-scattering by refractive-index-matching. Biological implications of increased light-transmission through epidermis at high ambient humidity are discussed.展开更多
We describe a technique for micro-patterning and immobilization of dyes on polymer substrates using a low-power visible laser for dye-excitation. Deposits from an aqueous medium containing the dye can be attached at a...We describe a technique for micro-patterning and immobilization of dyes on polymer substrates using a low-power visible laser for dye-excitation. Deposits from an aqueous medium containing the dye can be attached at any desired spot on the substrate simply by exposing the area to laser light. The area of the laser beam can control the spot-size of immobilized dye, in the range of 10 - 100 microns. The immobilization technique is characterized by micro-printing numerals, alphabets and patterns on polybutadiene substrates with Rhodamine (Rh6G) dye. Adsorption of laser-excited dye molecules within the polymer appears to be the mechanism for laser-printing technique.展开更多
文摘In the construction industry, silicone is primarily used as sealant material to fill gaps and cracks providing water and air-tightness to vertical construction projects reducing energy usage bills and enhancing the integrity of construction materials. This paper reports the results of spectral analysis of commonly used building sealant materials used in residential and commercial buildings. A dozen commercially available silicone-based sealant materials composed of different ingredients representing three manufacturer brands are characterized using Raman and UV-VIS-NIR spectroscopic techniques. The characteristic vibrational fingerprints of the selected sealant materials are summarized, and the Raman and reflectance spectra of the samples are also presented. It is observed that most of the samples appear to have similar vibrational band assignments and reflectance spectra. However, analysis of the Raman spectral positions and the reflectance spectra reveals that there are distinct differences among the sealant materials.
文摘Transmission of light through model human epidermal samples is investigated at four different wavelengths and at varying ambient humidity. Light from light emitting diodes (LEDs) is used for transmission measurements through the samples at a UVA wavelength of 365 nm, and visible wavelengths of 460 nm, 500 nm, and 595 nm. Ambient air-humidity is varied between 20% and 100%. Results show that for high ambient humidity, near 100%, transmission of light through the epidermis is higher than at low ambient humidity, 60% or lower. These results are explained with a simple model of epidermis as a turbid medium and the effect of adsorbed water in reducing light-scattering by refractive-index-matching. Biological implications of increased light-transmission through epidermis at high ambient humidity are discussed.
文摘We describe a technique for micro-patterning and immobilization of dyes on polymer substrates using a low-power visible laser for dye-excitation. Deposits from an aqueous medium containing the dye can be attached at any desired spot on the substrate simply by exposing the area to laser light. The area of the laser beam can control the spot-size of immobilized dye, in the range of 10 - 100 microns. The immobilization technique is characterized by micro-printing numerals, alphabets and patterns on polybutadiene substrates with Rhodamine (Rh6G) dye. Adsorption of laser-excited dye molecules within the polymer appears to be the mechanism for laser-printing technique.
