Search results for "LIGHT"

Indoor lighting quality: Effects of different wall colours

2016

This paper reports the results of measurements performed in a test room to investigate the impact of using different wall colours and light scenes on indoor lighting quality. Eye level spectral irradiances were measured for a user located inside the room and seated at a desk. These measurements allow the use of the Irradiance Toolbox, which makes it possible to calculate equivalent illuminances for the photopigments in the human eye. Moreover, the CIECAM02 colour appearance model was used to investigate the variations in hue and chroma values of the different wall colours when changing the light scene. The results demonstrate that there are significant variations in eye level spectral irra…

A Simulation of daylight levels for the determination of visual comfort in large spaces

2007

In sizable environments, such as the collective areas of a big university building, characterised by very long corridors, large hallways and broad glazed surfaces, the daytime illumination factor is often only excellent near to the latter, due to their predominantly horizontal, rather than vertical, nature. His study, which has been carried out thanks to a simulation software, shows the results of a correlation between light contributions, come out from the wide glass surface and those of a big skylight which cross lenghtways the main part of the building. Such results have been compared with some instrumental measurements considering the shifting and getting from them important information…

Assessing lighting quality in indoor environments

Study of Influence of the LED Technologies on Visual and Subjective/Individual Aspects

2018

The general aim of this paper is that to further deepen and elaborate the results obtained in a previous study of the authors, in which the relationship between the characteristics of five different types of LED lamps and the humans non-image-forming reactions were investigated, by conducting a more detailed statistical analysis and by highlighting the neurological aspects.

RESEARCH ON MICROCLIMATE LIGHT CONDITIONS IN A SCHOLASTIC ENVIRONMENT, BASED ON ADAPTIVE MODEL

2010

This paper shows the results of a deep research, carried out on a scholastic setting and based on a questionnaire, to evaluate the light microclimate and the satisfaction degree of the users. Through simulations, we have previously identified a number of classrooms where the conditions could be critical, both in terms of over-lightning, glare and disrespected values (suggested by the current normative). The proposed method consist in using device-made-surveys, a simulation software and questionnaires submission to users of the studied rooms. The questionnaires, based on an adaptive model, has been developed to detect subjective data (place, visus…) and other information about the setting an…

Electrochemical fabrication of Cu2O/TiO2 nanotubes junctions with visible light photoactivity

2013

Facile preparation of CuBi2O4/TiO2 hetero-systems employed for simulated solar-light selective oxidation of 4-methoxybenzyl alcohol model compound

2023

The selective photocatalytic oxidation of organic substances is today considered one of the green techniques to synthesize important starting materials in different technological applications. This work reports an efficient, simple and cheap strategy for the synthesis of a new photocatalytic CuBi2O4-TiO2 (CBO/TiO2) heterosystem at room temperature. The prepared powders were characterized by X-ray diffraction (XRD), UV–Vis diffuse reflectance spectra (DRS), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The photocatalytic activity was evaluated by performing a probe reaction, namely the partial oxidation of 4-me…

Photoelectrocatalytic reactors and light sources

2023

Photoelectrocatalysis (PEC) couples electrochemical methods with photocatalysis (PC) to enhance the separation of the photoproduced electron and hole pairs at semiconductor active surface, thus increasing the photocatalytic efficiency. PEC technology is considered one of the most promising method for processes as water treatment, fuel generation, and PEC sensing. This chapter try to link fundamental research and practical applications in photoelectrochemical engineering including reactors design strategies in different scales.

Two-Dimensional Modeling of an Externally Irradiated Slurry Photoreactor

2013

Abstract A batch cylindrical photocatalytic reactor, externally irradiated by 1–6 UV fluorescent lamps and containing a stirred slurry of polycrystalline TiO2, was modeled by coupling a modified Langmuir–Hinshelwood kinetics together with a two-dimensional light intensity field. The radiation field has been determined on the main assumptions of diffuse radiation, isotropic scattering and negligible backward reflected photon flow. The model has been applied to the photocatalytic oxidation of organic substrates which do not undergo homogeneous photochemical degradation. The model is characterized by the following four parameters: the kinetic constants of substrate adsorption, desorption and d…

Visible Light Induced Oxidation of Ferulic Acid by TiO2 Photocatalysis

2012

Oxidation of ferulic acid (C10H10O4) in aqueous medium occurs by using both commercial and home prepared TiO2 samples under visible light irradiation. Among the oxidation products vanillin was found with a selectivity ranging from 1 to 2% with respect to the converted substrate. By considering that TiO2 is unable to absorb visible light and ferulic acid does not react in the absence of TiO2, the observed photoactivity may be explained by the formation of a charge-transfer complex between ferulic acid and TiO2, being the complex able to absorb visible light. Among all the tested semiconductor oxides, only Merck anatase TiO2 does not perform the oxidation of ferulic acid under visible light i…