Cary 5000 uv vis nir

A sample of 30 mg G/TiO₂ hybrid was mixed with 25.0 mL (10 mg/L) methyl blue (MB) solution. After 4 hours of vigorous shaking under fluorescent light, 5.0 mL solution was collected and subsequently diluted by 10.0 mL DI water. The obtained solution was analyzed by a UV-Vis spectrometer (Varian Cary 5000 UV-Vis NIR) by recording the absorbance. The absorbance of characteristic peak at 664 nm is proportional to the concentration of MB45 (link) according to the Lambert-Beer’s Law. After the first cycle of evaluation, the G/TiO₂ hybrid was collected by gravity settling and subsequently washed by DI water for 3 times and dried in an oven. The dried G/TiO₂ hybrid was used for the next cycle of evaluation through the same procedures.

To investigate the UV reflection intensity in juvenile and adult Epicadus heterogaster we measured spectral reflectance between 300 and 700 nm in the abdomen of the spiders, in the petals of flowers (n = 10 young) and on the leaves of Miconia sp. (Melastomataceae) (n = 10 adults). We used a Cary 5000 UV- Vis- NIR (Varian, Australia) spectrophotometer with a high photometric performance in the spectral range of 175–3300 nm. We used two achromatic controls: black and white as calibration backgrounds prior to measuring each sample. We measured the spectra of spiders, leaves, and flowers 10 times and used the average number of spectra to compute the Euclidian distance in the color space model of the visual system of Hymenoptera^{35 , 36 (link)}. All measurements are done with the same color morph (i.e., white). We carried out the analyses in the Laboratório de UV-Vis-NR/Luminescência/Polarimetria at the Instituto de Química da Universidade Estadual de Campinas (UNICAMP).

In this work, we choose fluorescent light as the light source for sample treatment out of the consideration of future practical applications. The ultraviolet radiation in fluorescent light is able to initiate the photocatalytic reaction for the removal of pollutants. A sample of 30 mg G/TiO₂ hybrid was added into 25.0 mL (400 μg/L) potassium dichromate solution. After 4 hours of vigorous shaking under fluorescent light (SYLVANIA T5 fluorescent lamp, 28 W, 2 meters distance between the sample and lamp), 10.0 mL solution was collected and mixed with 0.2 mL phosphoric acid (85 wt%) and 0.5 mL coloring agent (1,5-diphenylcarbazide, DPC, 2.0 g/L)43 . The obtained solution was analyzed by a UV-Vis spectrophotometer (Varian Cary 5000 UV-Vis NIR) by recording the absorbance. The absorbance of the characteristic peak at 540 nm is proportional to the concentration of chromium (VI) ion44 (link) according to the Lambert-Beer’s Law. After the first cycle of evaluation, the G/TiO₂ hybrid was collected by 2 minutes of gravity settling and subsequently washed by DI water for 3 times and dried in an oven. The dried G/TiO₂ hybrid was used for the next cycle of evaluation through the same procedures.

The photocatalytic activities of all the samples were evaluated by the degradation of organic dyes (10 mg/L methyl blue) under simulated sunlight, which was obtained from a 300 W Xenon lamp (Newport Corporation, Irvine, CA, USA). Control experiments under visible light and UV light were also carried out to better understand the mechanism of the photocatalyzed reactions. The simulated sunlight (200–20000 nm), visible light (420–630 nm), and UV light (280–400 nm) were obtained by using different mirrors on the same instrument. In each experiment, 0.010 g catalyst (TiO₂-S/rGO hybrid, TiO₂, TiO₂-S, or TiO₂/rGO) was dispersed in 50.0 mL (10 mg/L) methyl blue (MB) solution. After stirring in the dark for 30 minutes to reach adsorption equilibrium, the light was turned on for testing. A sample of 3.0 mL well-dispersed suspension containing photocatalyst particles was collected periodically. The collected suspension was centrifuged to remove the photocatalyst particles and the obtained supernatant was analyzed by UV-Vis spectroscopy (Varian Cary 5000 UV-Vis NIR). The absorbance of the characteristic peak at 664 nm is proportional to the concentration of MB54 (link) according to the Beer-Lambert Law.

Color measurements were performed by a reflectance spectrophotometer (CARY 5000 UV-Vis-NIR; Agilent, Santa Clara, US) equipped with a DRA-1800 integrating sphere. Enamel blocks with sound, demineralized and sealed enamel were positioned over a standard white background. A dark mask containing an opening measuring 4 mm in diameter was placed over the tooth surface to set the limits of analysis. The color of each specimen was measured and quantified in terms of three coordinate values (L*, a* and b*) (n = 5). The color of the sound, demineralized and sealed enamel was assessed and recorded (M1, M2 and M3, respectively) under standardized conditions according to CIE L*a*b* system. The differences on the parameters obtained (ΔL*, Δa* and Δb*) were calculated by M1, M2 and M3. Comparisons between sealed enamel block color and sound enamel (M1 × M3) and demineralized enamel (M2 × M3) were calculated. The overall changes in color impression (ΔE) were calculated using the following formulas: $$\mathrm{\Delta }E1=\sqrt{{(LM3-LM1)}^2+{(aM3-aM1)}^2+{(bM3-bM1)}^2}$$ $$\mathrm{\Delta }E2=\sqrt{{(LM3-LM2)}^2+{(aM3-aM2)}^2+{(bM3-bM2)}^2}$$