Search results for "lighting"

Phosphorescent hybrid organic-inorganic light-emitting diodes.

2010

Rīgas apgaismes tehnikas rūpnīcas darbība no 1958.-1991.gadam

2016

PSRS rūpniecības vēsture ir interesanta un maz pētīta nozare, kas aktuāla arī mūsdienās, jo sekas atstājušas ietekmi ne tikai uz ekonomiku, bet arī uz lielas sabiedrības daļas domāšanas veidu. Tādēļ nepieciešami jauni pētījumi, kas raksturotu un analizētu PSRS ekonomikas pozitīvos un negatīvos aspektus. Uzmanība pievērsta konkrētam rūpniecības uzņēmumam - Rīgas apgaismes tehnikas rūpnīcai. Rūpnīcas darbībā redzamas problēmas, ko sagādāja ekonomikas plānošana pa piecgades periodiem, kas bija jāizpilda par katru cenu, neraugoties uz neprecīzajiem aprēķiniem un nepielāgojoties tirgus situācijai. Tas noveda pie izejmateriālu deficīta, sliktas kvalitātes ražojumiem un nespējas konkurēt ne tikai …

Integrated experimental and theoretical study on the phase transition and photoluminescent properties of ZrO2:xTb3+ (x=1, 2, 4 and 8 mol %)

2021

Abstract Zirconia (ZrO2) has been intensively studied as an important ceramic material, and numerous technological applications have been found. The present work deals with synthesizing and characterizing the phase transition (cubic vs tetragonal) and photoluminescence emissions of ZrO2:xTb3+ (x = 1,2,4 and 8 mol%). The samples formed by the complex polymerization were thoroughly characterized for physicochemical properties such powder by X-ray diffraction (XRD), and Raman and diffuse reflectance spectroscopies. First-principle calculations at the density functional theory level were performed to complement and rationalize the experimental results. An energy transfer mechanism which promote…

Twofold coordinated Ge defects induced by gamma-ray irradiation in Ge-doped SiO2

2008

We report an experimental study by photoluminescence, optical absorption and Electron Paramagnetic Resonance measurements on the effects of exposure of Ge-doped amorphous SiO2 to gamma ray radiation at room temperature. We have evidenced that irradiation at doses of the order of 1 MGy is able to generate Ge-related defects, recognizable from their optical properties as twofold coordinated Ge centers. Until now, such centers, responsible for photosensitivity of Ge-doped SiO2, have been induced only in synthesis procedures of materials. The found result evidences a role played by gamma radiation in generating photosensitive defects and could furnish a novel basis for photosensitive pattern wr…

Spotlighting phase separation in Rashba spin-orbit coupled Bose–Einstein condensates in two dimensions

2018

Through-focus response of multifocal intraocular lenses evaluated with a spatial light modulator

2012

A new testing technique based on the use of a liquid crystal spatial light modulator (SLM) is proposed to analyze the optical quality of multifocal intraocular lenses (MIOLs). Different vergences and decentrations of the incident beam can be programmed onto the SLM in order to record the point spread function (PSF) for different object positions. From these axial PSFs, the through-focus modulation transfer function is computed. Because there are no moving parts in the experimental setup, this method is fast and versatile to assess MIOLs. Experimental results confirm the potential of the proposed method.

Cultural content of lighting for the discovery of archaeological heritage

2013

Archaeological sites, built landscapes of the past, represent the identity heritage for future generations. The aim of this article is to investigate and demonstrate the importance of the cultural identity reinforcement, which can be achieved by enhancing the historical heritage through the use of artificial lighting. The charm of an archaeological site or a monument comes from the perception of its whole environmental context, both for the functional lighting and the enhancement of the artistic and monumental. Light can turn into concrete matter both in interiors, in archaeological and urban spaces: combining innovative technologies, artificial light can be used to change the world, to sha…

Images perceived after chromatic or achromatic contrast sensitivity losses.

2010

Purpose. We simulate how subjects with losses in chromatic and achromatic contrast sensitivity perceive colored images by using the spatiochromatic corresponding pair algorithm. Methods. This is a generalized version of the algorithm by Capilla et al. (J Opt Soc Am (A) 2004;21:176 –186) for simulating color perception of color deviant subjects, which incorporates a simple spatial vision model, consisting of a linear filtering stage, with a band-pass achromatic filter and two low-pass chromatic ones, for the red-green and blue-yellow mechanisms. These filters, except for the global scaling, are the subject’s contrast sensitivity functions measured along the cardinal directions of the color s…

Aspects and issues of daylighting assessment: A review study

2016

Abstract Proper assessment of indoor daylighting conditions can significantly reduce energy consumption due to artificial lighting and can improve indoor visual comfort. This paper gives a critical review of the fundamental aspects of daylighting indices with the aim to provide a broad overview of methods and indices available to assess daylighting from varying points of view. Assessments cover distribution, availability over time and in specific climatic contexts, uniformity in the space, visual comfort issues and the relations between each of these aspects and a proper building and lighting design. A special focus on the assessment of indoor spatial and temporal uniformity is given. An an…

Technical‐economic evaluation of the effectiveness of measures applied to the artificial lighting system of a school

2021

Ensuring optimum interior lighting is a topic of great importance, as this influences not only the well-being of users but also the optimal performance of visual tasks. Lighting can be natural, but if not sufficient, it can be compensated with artificial lighting. This study highlights a methodology for designing a new lighting system that takes into account both technical and economic aspects. The method was applied to an existing school located in southern Italy, in which the electricity consumption is related to the current lighting system. The school is chosen as being representative of the construction type and layout of many local schools. In addition, the coexistence of several visua…