Search results for "daylight."
showing 10 items of 44 documents
Lighting in educational environments: An example of a complete analysis of the effects of daylight and electric light on occupants
2013
Abstract Light induces not only visual responses but also non-visual effects, indeed it affects performance, mood, attention and influences the synchronization of the biological clock. Duration, timing, intensity and the spectral power distribution of the light that reaches the eyes can have influence on human circadian rhythm and consequently on health. Given the important impact of the non-visual responses on people wellbeing, developing a model that allows lighting designers to predict them is a fundamental goal. In this paper a case study is reported: a series of measurements were carried out in a University classroom in order to study daylight and electric light characteristics and als…
Performance of the Glass Block in Photovoltaic Generation
2015
In this article is presented the preliminary evaluation of the performance of radiation transmission of glass block, used in support of photovoltaic cells, investigating different internal surface points of the block, which are subject to different shading during daylight hours. The aim is to establish how the edging setting, the only opaque element, can reduce the amount of light radiation during the day, introducing in this way a reduction of efficiency of the entire generation system. The generation system can be based on traditional photovoltaic cells or on the most suitable dye sensitized solar cells. An experimental measurement setup employing a microprocessor-based instrument has bee…
Lighting control systems: Factors affecting energy savings' evaluation
2015
Abstract The use of automated lighting control systems allows to reduce lighting costs and to achieve significant energy savings. The energy performances of controls are affected by many factors, the impact of which is very difficult to account for during the design process. The goal of this paper is to describe the factors that influence the control systems’ energy performances, to analyze how the currently available calculation tools take them into account and finally to propose a simple method to adjust results obtained from the simulation software.
Energy Savings through Integration of the Illumination Natural and Artificial, Using a System of Automatic Dimming: Case Study
2013
The reduction of electrical energy consumption in buildings is a subject of great interest in the international scientific community. In buildings with a lot of available natural light, designed with large glazed surfaces, the artificial lighting system is often oversized and cannot be divided into segments to meet lighting demands during daylight hours.This article presents an experimental study, conducted in a university lecture hall that has a glazed surface covering the whole wall at one end, which provides a level of internal illumination that is only sufficient for the area next to the window itself, even when the outside lighting conditions are very bright. It is therefore necessary …
Winter and summer analysis of daylight characteristics in offices
2014
Abstract This paper reports a comparison of the results of daylight measurements carried out in summer and winter in three offices, with different exposures and characteristics, located in Naples (Italy). The aim was to extend and enrich the findings of a previous study which reported the results of summer measurements about desk illuminances and circadian impact. The research project includes measurements carried out in other seasons and a comparison between measured and software simulated values with the final goal of developing design guidelines. This research confirmed that the spectral distributions and CCTs of the light reaching the eye of a person seated at the desk in these offices …
Questionnaires and simulations to assess daylighting in Italian university classrooms for IEQ and energy issues
2021
Abstract Results from the DAYKE-Italy project are presented. An investigation on daylighting in eight classrooms in five Italian universities was carried out through a combined approach: an ad-hoc survey administered to students to investigate how they perceive daylight in classroom, and numerical simulations (DIVA + ALFA) to calculate a set of objective metrics (daylight, circadian, and energy-related). A sample of 542 questionnaires was collected through two sessions and the subjective judgments were correlated to objective metrics. Results from descriptive and statistical analyses showed: (i) the correlation was significant for all daylight metrics: among them, average daylight factor an…
Absence of lightness constancy as a deficit of monochromatic vision
1995
Dark-adapted human subjects arranged a collection of colored papers in a sequence according to their lightness. The sequence of the papers (which appeared gray to the subjects) varied under different illuminant spectra. These variations could be predicted quantitatively from the radiometric data and human scotopic spectral sensitivity. By substitution of natural daylight spectra in the computation it was shown that monochromats cannot perceive lightness reliably under the changing illuminant spectra of our planet. Animals need some degree of lightness constancy to detect figures against a background reliably. This can be achieved only with the help of additional light receptors of different…
Effect of pinealectomy and circadian rhythm on avoidance behavior in the male rat.
1985
Male adult albino rats were divided into six groups: two pinealectomized (Px); two sham-operated (Sh) and two serving as controls (C). Half of these groups were studied in daylight and the other half at night. The animals were open-field tested and then conditioned by the avoidance behavior test in the appropriate light period. No differences were observed among the groups when they were conditioned in the dark; however, the Px were conditioned significantly more rapidly than Sh or C in daylight. Intragroup comparisons between night/day conditioning showed them to be similar in Px but more rapid at night in both Sh and C. The Sh group is unique and not comparable to controls.
Melatonin signaling modulates clock genes expression in the mouse retina.
2014
Previous studies have shown that retinal melatonin plays an important role in the regulation of retinal daily and circadian rhythms. Melatonin exerts its influence by binding to G-protein coupled receptors named melatonin receptor type 1 and type 2 and both receptors are present in the mouse retina. Earlier studies have shown that clock genes are rhythmically expressed in the mouse retina and melatonin signaling may be implicated in the modulation of clock gene expression in this tissue. In this study we determined the daily and circadian expression patterns of Per1, Per2, Bmal1, Dbp, Nampt and c-fos in the retina and in the photoreceptor layer (using laser capture microdissection) in C3H-f…
Programmatūras Definētas Tīklošanas tehnoloģijas darbības principi
2017
Līdz ar mākoņpakalpojumu sniedzēju un datortīklu skaita straujo pieaugumu, datortīklu prasības to projektēšanā un pārvaldībā kļūst aiz vien lielākas. Darbā tiek apskatītas programmatūras definētas tīklošanas darbības principi (SDN). Tas ir jauns tīkla dizaina princips, kura pamatdoma ir centralizēts kontrolieris kurš pārrauga tīkla darbību, kas tiek realizēts atdalot kontroles līmeni no datu līmeņa tradicionālajās tīkla iekārtās. Darbs sastāv no četrām nodaļām, kurās tiek apskatīta SDN daudzslāņu arhitektūra, iepazīti esošie SDN kontrolieru risinājumi, protokoli kādi tiek izmantoti un aprakstīts nepieciešamais minimums, lai izveidotu SDN tīklu mājas apstākļos.