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Background: Iodine has undeniable effects on human in all stages of life and its deficiency during fetal stages causes mental retardation, which incurs huge costs for treatment and care. Objectives: The aim of this study was to evaluate the effect of heat, humidity and light on the iodine content in iodized salt. Methods: In this analytical-descriptive study, five brands of refined iodized salts were randomly selected from supermarkets in Babol City. All tests were performed in the Chemistry Laboratory of Paramedical School in Babol University of Medical Sciences. In the current study, the samples were kept for three months under different conditions of humidity, without humidity, light, darkness, and temperatures of 37°C, refrigerator and ambient. The iodine amount of samples was tested every 15 days using titration method based on Britain Pharmacopoeia. Data were analyzed with ANOVA in SPSS. Results: The results showed that iodine was reduced in all samples of refined salts: 9.69 ± 1.3 for refrigerator temperature with humidity, 8.34 ± 1.4 for refrigerator temperature without humidity, 8.85 ± 1.2 for 37°C with humidity, 7.80 ± 1.4 for 37°C without humidity, 13.96 ± 1.3 for ambient temperature with light and humidity, 9.61 ± 1.5 for ambient temperature with light and without humidity, 8.64 ± 1.1 for ambient temperature with humidity in darkness, and 5.41 ± 1.2 mg/L for ambient temperature without humidity in darkness. Conclusions: The results indicated that ambient temperature, darkness and non-humidity were the best conditions for keeping iodized salt.

Improved optical side coupling efficiency was demonstrated for spiral patterned zinc oxide (ZnO) nanorods coated large core plastic optic fibers (POFs) as opposed to unpatterned continuous coatings. ZnO nanorods were grown by the hydrothermal method directly onto POF surfaces. Nanorods coating enhanced coupling inside the fiber by scattering light but were also capable of causing leakage. Structuring the growth to specific regions allows scattering from different segments along the fiber to contribute to the total coupled power. ZnO nanorods growth time of 12 h and temperature of 90 °C provided the best coupling voltage. Side coupling was measured to be a factor of 2.2 times better for spiral patterned coatings as opposed to unpatterned coatings. The formation of multiple segments was as well used for multiple-wavelength channels excitation where different bands were side coupled from different segments.

Detection of Carbon Monoxide gas is very vital issue in the environment. This study demonstrates a simple technique to detect Carbon Monoxide gas by Plasmon resonance peak shift in gold nanoparticles (NPs) coated on ZnO nanorods that are grown on the SiO2 surface. The structure is used to sense very low concentrations of CO gas (From 1 ppm to 15 ppm). Coating the NPs on to Zno Nanorods increases the surface-to-volume ratio and hence enhances the device sensitivity. This result allows to make a simple and precise sensor with quick and high response.

Controlled light coupling from surrounding to the cladding mode of zinc oxide (ZnO) nanorod coated multimode optical fiber induced by the light scattering properties of the nanorod coating and their applications of sensing are reported here. A dense and highly ordered array of ZnO nanorods is grown on the cladding of silica fibers by using low temperature hydrothermal process and the effect of the hydrothermal growth conditions of the nanorods on the light scattering and coupling to the optical fibers is experimentally investigated. The nanorod length and its number per unit area are found to be most crucial parameters for the optimum side coupling of light into the fibers. Maximum excitation of the cladding mode by side coupling of light is obtained with ZnO nanorods of length ∼2.2 μm, demonstrating average coupling efficiency of ∼2.65%. Upon exposure to different concentrations of various chemical vapors, the nanorod coated fibers demonstrated significant enhancement in the side coupled light intensity, indicating the potential use of these ZnO nanorod coated fibers as simple, low cost and efficient optical sensors. The sensor responses to methanol, ethanol, toluene and benzene vapor were investigated and compared, while the effect of humidity in the sensing environment on the sensor performance was explored as well.

This study experimentally demonstrates the feasibility of utilizing zinc oxide nanorods for CO and CO2 gas detection via optical scattering. ZnO nanorods are grown on a plastic optical fiber to measure the effect of gas flow on the optical scattering at room temperature. The presence of nanorods minimizes the coupling of the Fresnel reflection. Placing the optical setup in a home-built gas chamber, an obvious distinguished change of the total reflection was observed when different gas concentrations were present. Reduction of reflection due to the presence of gas indicated that forward scattering leak has a dominant effect on the process. In addition, the results demonstrated that detection of CO gas at a concentration as low as 200 ppm had a higher response in comparison with CO2 gas.

A novel concept is introduced that utilizes the scattering properties of zinc oxide nanorods to control light guidance and leakage inside optical fibers coated with nanorods. The effect of the hydrothermal growth conditions of the nanorods on light scattering and coupling to optical fiber are experimentally investigated. At optimum conditions, 5% of the incident light is side coupled to the cladding modes. This coupling scheme could be used in different applications such as distributed sensors and light combing. Implementation of the nanorods on fiber provides low cost and controllable nonlithography-based solutions for free space to fiber coupling. Higher coupling efficiencies can be achieved with further optimization.

This paper demonstrates a working indoor optical wireless link for smart environment applications. The system utilizes a wide field-of-view (FOV) optical wireless receiver through cleaving the tip of large core plastic optical fibers (POFs) attached to the detector. The quality of the optical link is quantified through bit error rate (BER) measurements. The experimental results show a wide FOV with the uncoded BER in the order of 10−3 for transmission distances up to 35 cm when using two POFs for signal collection. The distance can be improved further by increasing the number of fibers. The transmitted signal format and how the BER measurement is achieved are discussed at length. In addition, details are provided for the design of the electronics to establish the optical wireless link.

Side coupling to core modes through zinc oxide (ZnO) nanorods grown around the fiber is demonstrated in this work. The scheme utilizes wet etching of the cladding region followed by hydrothermal gr ...