The effect of light scattering on measurement of UV absorbance and penetration of germicidal UVC irradiance in a UV reactor were studied. Using a standard spectrophotometer, absorbance measurements exhibited significant error when particles that scatter light were present but could be corrected by integrating sphere spectroscopy. Particles from water treatment plants and wastewater effluents ex...

Abstract The most medically representative plant in the Apocynaceae family is Vinca minor . a perennial, herbaceous plant, commonly known as Saschiu. In present research we aimed to isolate indole compounds from L. and carry out some physico-chemical studies on these compounds: UV-VIS spectroscopy determination of polyphenols content using Folin-Ciocâlteu method. spectrophotometric study alcoho...

In the US Environmental Protection Agency methods for sediment toxicity testing, the light regimen is specified as a 16:8 light dark cycle with 500-1000 lx. The potential for photoinduced toxic effects from this requirement is evaluated. Hyalella azteca were exposed to fluoranthene in both water only and sediment to examine the impact of light spectra on the toxicity of fluoranthene. The light ...

This study examined the transport behavior of Aldrich humic acid (AHA) in low natural organic carbon content sediment contaminated with tetrachloroethene (PCE), for comparison to a nonionic surfactant mixture previously examined in the same system. Tracking of individual molecular weight (MW) fractions of AHA was attempted by UV absorbance, followed by conversion to mass of carbon using specifi...

Typically, the first thing one wants to know about a DNA preparation is its concentration and purity. Both can be determined by measuring the absorption of ultraviolet light. DNA absorbs UV more or less strongly depending upon the wavelength. We will be using a NanoDrop spectrophotometer, which takes measurements at wavelengths of 260 and 280 nm, and in addition determines an absorption spectru...

Natural light is a transverse electromagnetic wave with electric (E) and magnetic (H) fields perpendicular to each other (Fig. 1). The two fields are also perpendicular to the wave’s direction of travel (k). In unpolarized light the electric field vectors vibrate in all directions of the EH plane equally (Fig.2). Note that all the electric field vectors are of the same length. When the Polarize...

ZnS nanoparticles of different size have been synthesized using a colloidal particles method. ZnS nanoparticles prepared with capping agent (mercaptoethanol) then were characterized using X-ray diffraction (XRD) and UV-Vis spectroscopy. The particle size of the nanoparticles calculated from the XRD patterns has been found in the range 1.85-2.44nm. Absorption spectra have been obtained using UV-...

Skin cancer incidence in Croatia is steadily increasing in spite of public and governmental permanently measurements. It is clear that will soon become a major public health problem. The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet (UV) radiation. The future designers of UV protective materials should be able to block totally the ultraviolet radiation. The...

We propose an algorithm to retrieve the global features of the spectral dependence of the ultraviolet (UV) irradiance from integrated, broadband UV measurements performed with a set of photodiodes with different UV filters. This fit, when applied to ground-based measurements and compared with the incident Solar spectral irradiance on the top of the atmosphere, may be used to extract the spectra...