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[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]SPEE [ADD1_IRSTEA]Sûreté alimentaire; International audience; This article describes the planning, set-up, turbulence characterization and analysis of measurements of a passive grid turbulence experiment that was carried out in the S1MA wind-tunnel from ONERA in Modane, in the context of the ESWIRP European project. This experiment aims at a detailed investigation of the statistical properties of turbulent flows at large Reynolds numbers. The primary goal is to take advantage of the unequaled large-scale dimensions of the ONERA S1MA wind-tunnel facility, to make available to the broad turbulence community high-quality experimental turbulence data with unprecendented resolution (both spatial and temporal) and accuracy (in terms of statistical convergence). With this goal, we designed the largest grid-generated turbulence experiment planned and performed to date. Grid turbulence is a canonical flow known to produce almost perfectly homogeneous and isotropic turbulence (HIT) which remains a unique framework to investigate fundamental physics of turbulent flows. Here, we present a brief description of the measurements, in particular those based on hot-wire diagnosis. By comparing results from classical hot-wires and from a nano-fabricated wire (developed at Princeton University), we show that our goal of resolving down to the smallest dissipative scales of the flow has been achieved. We also present the full characterization of the turbulence here, in terms of turbulent energy dissipation rate, injection and dissipation scales (both spatial and temporal) and Reynolds number. © 2017, Deutsches Zentrum f

Ustrezna osvetljenost v šolskih prostorih je še posebej pomembna v razredu, saj omogoča učinkovito in produktivno spremljanje in izvajanje pedagoškega procesa. Zagotovitev ustrezne osvetljenosti šolskih prostorov se izvaja v skladu z predpisi iz Pravilnika o zahtevah za zagotavljanje varnosti in zdravja delavcev na delovnih mestih, v katerem so navedene zahteve za ustrezno osvetljenost na delovnem mestu. Pravilnik je sestavljen na osnovi Zakona o varnosti in zdravja pri delu in se sklicuje na uporabo veljavnega standarda SIST EN 12464, 1. in 2. del. Diplomsko delo se predvsem osredotoča na 1. del standarda, ki govori o osvetljenosti delovnih mest oz. površin v prostorih. Merjenje osvetljenosti delovnih površin in prostorov se izvaja z namenom ugotoviti ali so le-ti osvetljeni v skladu s predpisi, ki zagotavljajo varni in zdravju neškodljivo delovno okolje. Izvajanje in dokumentiranje meritev mora biti kadarkoli preverljivo in ponovljivo. Meritve osvetljenosti se izvajajo na tri načine. Prvi način je merjenje osvetljenosti pot vplivom naravne svetlobe. Drugi način je merjenje kombinirane osvetljenosti, kjer merimo osvetljenost delovnih površin in njihove neposredne okolice pod vplivom umetne in naravne svetlobe. Tretji način je merjenje umetne osvetljenosti, brez vpliva naravne svetlobe. Če delo poteka samo podnevi, si lahko pomagamo z merjenjem umetne osvetljenosti tako, da zastremo okna. Našteti načini merjenja so bili izvedeni v okviru diplomskega dela. V okviru diplomskem dela so bile izvedene meritve osvetljenosti delovnih mest v šolskih prostorih. Meritve so bile izvedene po predpisanih protokolih. V skladu s protokoli so bile za meritve izbrana naslednja delovna mesta: dve mizi, delovni pult, tabla in cel prostor - laboratorij. Po meritvah je bila izvedena analiza meritev ter primerjava rezultatov s predpisanimi vrednostmi minimalne osvetljenosti delovnih prostorov oz. površin kot jih predpisuje pravilnik, ki se sklicuje na standard SIST EN 12464. Ugotovljeno je bilo, da osvetljenost delovnih površin v fizikalnem laboratoriju, glede na predpise, ki navajajo zahteve za osvetljenost na delovnem mestu, ni ustrezna. V zaključku diplomskega dela so zato podani predlogi za izboljšanje osvetljenosti šolskih prostorov. Appropriate lighting in school spaces is especially important in classrooms as it enables efficient and productive learning and delivering of the education process. To ensure the most appropriate lighting in classrooms special regulations are being used. Conditions for appropriate lighting in workspaces are written in Rules on requirements for ensuring the safety and health of workers at the workplace. The rule book is constructed based on the Act on occupational safety and health and refers to the use of the valid standard SIST EN 12464, parts 1 and 2. This diploma work focuses primarily on the first part of the standard, which speaks about the lighting in workspaces. The purpose of measuring the lighting in workspaces is to identify the agreement between the actual lighting in workspaces and the regulations, which promise a safe and healthy work environment. Execution and documenting of the measurements must be provable and repeatable at all times. Measuring is executed in three different ways. The first is measuring of lighting by the influence of natural light. The second is measuring of the combined lighting. In this case we measure the combined lighting from natural and artificial light in the workspace and in its’ vicinity. The third way is the measuring of artificial lighting without the influence of daylight. The mentioned ways of measuring were carried out for the purposes of this diploma work. The measuring was carried out in school workspaces under regulated protocols. The following workspaces were chosen for measurements: the blackboard, two tables, the worktop and the whole laboratory. After the measurements were completed, they were analyzed and the results of the analysis were compared to the regulated requirements of the act that refers to the SIST EN 12464 standard for appropriate lighting in workspaces. The comparison showed that the lighting in the physics laboratory chosen for analysis does not meet all the regulations given by the rule book. Because of this, proposals for improving the lighting this laboratory are given in the conclusion.

et al., Studying thermal transport at the nanoscale poses formidable experimental challenges due both to the physics of the measurement process and to the issues of accuracy and reproducibility. The laser-induced transient thermal grating (TTG) technique permits non-contact measurements on nanostructured samples without a need for metal heaters or any other extraneous structures, offering the advantage of inherently high absolute accuracy. We present a review of recent studies of thermal transport in nanoscale silicon membranes using the TTG technique. An overview of the methodology, including an analysis of measurements errors, is followed by a discussion of new findings obtained from measurements on both >solid> and nanopatterned membranes. The most important results have been a direct observation of non-diffusive phonon-mediated transport at room temperature and measurements of thickness-dependent thermal conductivity of suspended membranes across a wide thickness range, showing good agreement with first-principles-based theory assuming diffuse scattering at the boundaries. Measurements on a membrane with a periodic pattern of nanosized holes (135nm) indicated fully diffusive transport and yielded thermal diffusivity values in agreement with Monte Carlo simulations. Based on the results obtained to-date, we conclude that room-temperature thermal transport in membrane-based silicon nanostructures is now reasonably well understood., The work done at MIT was supported as part of the “Solid State Solar-Thermal Energy Conversion Center (S3TEC),” an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0001299/DEFG02-09ER46577. The contribution by A.V.-F. and J. J. A.-G. was partially supported by Project 192 “Fronteras de la ciencia” and Project 251882 “Investigacion Científica Basica.” A. V.-F. also appreciates support from Conacyt through normal and mixed scholarships. MS and CMST acknowledge support from the Spanish program Severo Ochoa (Grant SEV-2013-0295), projects PHENTOM (FIS2015-70862-P) and nanoTHERM (CSD2010-00044), as well as from the EU project MERGING (309150). Z.L. and E.N.W. further acknowledge support and funding from the Air Force Office of Scientific Research (AFOSR), and are grateful to program manager Dr. Ali Sayir.

The article deals with the requirements to the quality of the carried-out measurements promoting metrological ensuring of production. The block-scheme of metrological ensuring of production is developed. Methods of increase of efficiency of metrological ensuring of production are enumerated. The analysis of the results of the measurements is carried out Рассмотрены требования к качеству выполняемых измерений, способствующих метрологическому обеспечению производства. Разработана блок-схема метрологического обеспечения производства. Перечислены методы повышения эффективности метрологического обеспечения производства. Проводится анализ результатов измерений