Selection of the method for calculating the thermal conditions in the optical elements of lasers

1972 ◽  
Vol 1 (5) ◽  
pp. 489-495
Author(s):  
B R Belostotskii
Keyword(s):  
Thermal Conditions ◽  
Optical Elements ◽  
Selection Of

scholarly journals Arbitrary polarization conversion for pure vortex generation with a single metasurface

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 727-732
Author(s):  
Marco Piccardo ◽  
Antonio Ambrosio
Keyword(s):  
Angular Momentum ◽  
Polarization Conversion ◽  
Vortex Beam ◽  
Vortex Generation ◽  
Optical Elements ◽  
Amplitude Control ◽  
Cavity Resonators ◽  
Vortex Beams ◽  
Topological Charges ◽  
Selection Of

AbstractThe purity of an optical vortex beam depends on the spread of its energy among different azimuthal and radial modes, also known as $\ell $- and p-modes. The smaller the spread, the higher the vortex purity and more efficient its creation and detection. There are several methods to generate vortex beams with well-defined orbital angular momentum, but only few exist allowing selection of a pure radial mode. These typically consist of many optical elements with rather complex arrangements, including active cavity resonators. Here, we show that it is possible to generate pure vortex beams using a single metasurface plate—called p-plate as it controls radial modes—in combination with a polarizer. We generalize an existing theory of independent phase and amplitude control with birefringent nanopillars considering arbitrary input polarization states. The high purity, sizeable creation efficiency, and impassable compactness make the presented approach a powerful complex amplitude modulation tool for pure vortex generation, even in the case of large topological charges.

Evaluation of a permissible roadbed thawing depth in permafrost

2021 ◽  
Vol 5 ◽  
pp. 18-22
Author(s):  
Alexandr Galkin
Keyword(s):  
Thermal Resistance ◽  
Biot Number ◽  
Seasonal Changes ◽  
Construction Materials ◽  
Thermal Conditions ◽  
Road Base ◽  
Thawing Depth ◽  
Roadway Construction ◽  
Selection Of ◽  
Purpose Of Evaluation

Roadbed thermal conditions in permafrost are subject to seasonal changes affecting roadway resilience. A roadbed thawing depth is important for road base processing, especially in permafrost. This research had the purpose of evaluation of a permissible roadbed thawing depth based on the Biot number reflecting general thermal resistance of roadbed layers. These results will contribute to understanding road bed thermal resistance and selection of roadway construction materials.

The Optimum Energy Saving Measures for Retrofitting Residential Buildings

2016 ◽  
Vol 41 (1) ◽  
pp. 88-92
Author(s):  
Rong-Yue Zheng ◽  
Jian Yao
Keyword(s):  
Energy Saving ◽  
Energy Savings ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
High Energy ◽  
Cold Winter ◽  
Efficiency Measures ◽  
Optimum Energy ◽  
Potential Energy Saving ◽  
Selection Of

A large number of residential buildings in hot summer and cold winter zone of China are non-energy efficient with poor indoor thermal conditions. Retrofitting residential buildings with energy efficiency measures is thus important for residents. However, this work progressed slowly because practically applicable measures that not only have high energy savings but also improve indoor thermal performance have not been studied. Thus, this paper carried out a simulation study on the selection of suitable energy saving measures for residential buildings in hot summer and cold winter zone of China. Five potential energy saving options are considered and the energy, indoor thermal comfort and economic performance are compared. The results show that adding movable solar shades is the optimum option with all performance indices ranking first. Meanwhile, this measure is also the only acceptable energy saving solution for residents since its payback period is less than the lifespan of a building. As a conclusion, it is recommended to use movable solar shades as a first priority when retrofitting residential buildings.

scholarly journals Temperature-Based Grapevine Ripeness Modeling for cv. Touriga Nacional and Encruzado in the Dão Wine Region, Portugal

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1777
Author(s):  
Pedro Rodrigues ◽  
Vanda Pedroso ◽  
Fernando Gonçalves ◽  
Samuel Reis ◽  
João A. Santos
Keyword(s):  
Thermal Conditions ◽  
Rate Coefficients ◽  
Maturity Stage ◽  
Sigmoid Function ◽  
Total Acidity ◽  
Regression Analyses ◽  
Heat Accumulation ◽  
High Fraction ◽  
Wine Region ◽  
Selection Of

In the present study, we calibrated and validated thermal models to predict the DOY date at which the grape maturity index, potential alcohol/total acidity (PA/TA), reaches 0.75 (MS0.75), 1.0 (MS1), 1.5 (MS1.5), and 2.0 (MS2) for two grapevine Portuguese varieties, Touriga Nacional (TN) and Encruzado (EN), growing in the Dão wine region, Portugal. Daily rates of forcing calculated with the Sigmoid function (SM) and the Degree Day function (DD) were used. The outcomes show that the best performance of the models was obtained for the heat accumulation starting at flowering (tx = EL23). The analysis of model sensitivity to changes in forcing rate coefficients (T0, e, and d) enabled the selection of the same models for all maturity stage of each variety. The selected models revealed significant predictability, though dependent on the grape maturity stage and variety (EFF > 0.81 for TN and EFF > 0.75 for EN). The non-linear regression analyses of sugar concentration (SC) and total acidity (TA) with heat accumulation, calculated using the select models, demonstrated that a high fraction of SC and TA variance was explained by the variation of these temperature-based indices. Comparatively to SC and TA, the results highlight that the thermal conditions accumulated from flowering had a lower influence on pH juice variance.

Selection of angular harmonics by the use of diffractive optical elements

2001 ◽  
Author(s):  
Victor V. Kotlyar ◽  
Svetlana N. Khonina ◽  
Victor A. Soifer ◽  
Marko Honkanen ◽  
Jari P. Turunen
Keyword(s):  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Selection Of

scholarly journals STUDI PENGARUH BAHAN PENUTUP ATAP TERHADAP KONDISI TERMAL PADA RUANG ATAP

2017 ◽  
Vol 1 (1) ◽  
pp. 35
Author(s):  
Amat Rahmat ◽  
Eddy Prianto ◽  
Setia Budi Sasongko
Keyword(s):  
Surface Temperature ◽  
Energy Use ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
Heat Radiation ◽  
Air Cooling ◽  
Roof Shape ◽  
Roofing Material ◽  
Roofing Materials ◽  
Selection Of

Abstract:. The uncomfortable thermal conditions in the building are complained of by the inhabitants due to the inappropriate selection of roofing materials, thus making the building unable to achieve the expected thermal conditions. Selection of appropriate roofing material will help in air cooling process and minimize energy use for cooling space. This study was conducted to determine the thermal conditions of roof space generated from various types of roofing materials that have been determined. The study object of this study is the roof space in residential buildings with a saddle roof shape with a slope of 30O roof angle. Roofing material is tile, asbestos and zinc. The results data show that the average thermal spaces of roof space on tile roofs are 1.91OC-2.31OC lower than the asbestos roof and zinc. Roof tile is also more able to withstand the sun's heat radiation. The average surface tile roof temperature is 0.28˚C lower than the surface temperature of the asbestos roof and 1.55˚C lower than the zinc roof surface temperature. However, the average profile of the lowest roof surface temperature during the daytime is on the asbestos roof (38.71˚C). Keyword: Roofing material, Thermal condition, Roof room Abstrak: Kondisi termal yang tidak nyaman pada bangunan banyak dikeluhkan oleh penghuni karena pemilihan material atap yang tidak sesuai, sehingga menjadikan bangunan tidak dapat mencapai kondisi termal yang diharapkan. Pemilihan material penutup atap yang tepat akan membantu di dalam proses pendinginan udara serta meminimalisir penggunaan energi untuk pendinginan ruang. Penelitian ini dilakukan untuk mengetahui kondisi termal ruang atap yang dihasilkan dari berbagai jenis bahan material atap yang sudah ditentukan. Objek studi dari penelitian ini adalah ruang atap pada bangunan rumah tinggal dengan bentuk atap pelana dengan kemiringan sudut atap 30O. Bahan penutup atap adalah genteng, asbes dan seng. Data hasil penelitian menunjukkan bahwa rata-rata termal ruang atap pada atap genteng lebih rendah 1.91OC-2.31OC dari atap asbes dan seng. Atap genteng juga lebih dapat menahan radiasi panas matahari. Rata-rata nilai temperatur permukaan atap genteng lebih rendah 0.28˚C dari temperatur permukaan atap asbes dan 1.55˚C lebih rendah dari temperature permukaan atap seng. Namun rata-rata profil temperatur permukaan atap terendah saat siang hari adalah pada atap asbes  (38.71˚C).Kata Kunci: Bahan penutup atap, Kondisi termal, Ruang atap

scholarly journals Evaluation of winter temperatures on apple budbreak using grafted twigs

2013 ◽  
Vol 35 (3) ◽  
pp. 713-721 ◽  
Author(s):  
Fernando José Hawerroth ◽  
Flavio Gilberto Herter ◽  
José Luiz Petri ◽  
Anderson Carlos Marafon ◽  
Jeison Furtado Leonetti
Keyword(s):  
Thermal Conditions ◽  
Yield Potential ◽  
Winter Period ◽  
Chilling Requirement ◽  
Dormancy Period ◽  
Winter Temperatures ◽  
Apple Cultivars ◽  
One Year ◽  
Efficient Selection ◽  
Selection Of

Temperature is the main climate factor related to induction, maintenance and dormancy release in apple (Malus domestica Borkh.). The inadequate chilling exposure in apples causes budbreak problems, resulting in decrease in yield potential. Thus, the knowledge of physiological principles and environmental factors determining the dormancy phenomenon, especially winter temperature effects, it is necessary for the efficient selection of cultivars in a productive region. In addition, it is indispensable to adapt the orchard management aiming to decrease the problems caused by lack chilling during winter. The objective of this study was to evaluate the influence of different thermal conditions during the dormancy period on budbreak of apple cultivars. One-year-old twigs of 'Castel Gala' and 'Royal Gala' cultivars, grafted on M7 rootstock, were submitted to temperatures of 5, 10 and 15ºC for different exposure periods (168; 336; 672; 1,008 and 1,344 hours). After treatments execution, the plants were kept in a greenhouse at 25ºC. Budbreak was quantified when accumulated 3,444; 6,888; 10,332; 13,776; 17,220 and 20,664 GDHºC after temperature treatments. The cultivars responded differently to temperature effect during the winter period. The temperature of 15ºC during winter shows a greater effectiveness on 'Castel Gala' apple budbreak while in the 'Royal Gala' apples the temperatures of 5 and 10ºC show better performance. 'Castel Gala' cultivar (low chilling requirement) may supply its physiological necessities, may be capable to budburst, even when subjected to higher temperatures in relation to 'Royal Gala' apples (high chilling requirement).

Stray light and ghosts in catadioptric spectrometers: incorporating grating scatter measurements into simulations and ghost sensitivity into system design

2018 ◽  
Vol 7 (6) ◽  
pp. 377-386 ◽  
Author(s):  
Monika Kroneberger ◽  
Andreas Mezger ◽  
Stephanie Becker
Keyword(s):  
High Sensitivity ◽  
Stray Light ◽  
Multiple Diffraction ◽  
Optical Elements ◽  
Optical Instruments ◽  
Light Requirements ◽  
Measurement Results ◽  
Selection Of

Abstract The accurate simulation of stray light is essential for the verification of the contrast requirements in optical instruments. In a spectrometer, the scattering from reflective gratings is difficult to characterize while contributing significantly to the overall system stray light and reduction of the spectrometer contrast. In addition, the multiple diffraction orders create a ghost sensitive environment, which must be considered in the design of the instrument. In this article, we present an experimental setup for, and measurement results from, the characterization of the bidirectional scattering distribution function (BSDF) of a holographic grating for a spectrometer applied in a typical earth observation mission with demanding stray light requirements. We observed distinct stray light peaks out of the diffraction plane, which are called ‘satellites.’ The main challenges in the measurement of grating BSDFs arise from the near angle limit, the determination of the instrument signature and the selection of the appropriate sampling (2D or 3D). Following the grating characterization, the next step is to introduce these measured BSDFs into stray light simulation. We have done that by fitting appropriate functions to the measured BSDF and defining them in the optical analysis software ASAP as a user-defined BSDF. Ghost analysis is done at the spectrometer level as a sensitivity analysis of the tilts of the optical elements. Due to the ghosting of higher diffraction orders of the grating, a high sensitivity to the tilts of some of the optical elements can be seen.

Optical glass: standards – present state and outlook

2015 ◽  
Vol 4 (5-6) ◽  
Author(s):  
Peter Hartmann
Keyword(s):  
Water Resistance ◽  
Optical Glass ◽  
Optical Element ◽  
International Organization ◽  
Optical Elements ◽  
Glass Quality ◽  
Element Size ◽  
Backward Compatibility ◽  
Cover Material ◽  
Selection Of

AbstractIn 1996, the international organization for standardization ISO started the standards series ISO 10110 specifying indications in drawings of optical elements. Three parts cover material properties: part 2 (stress birefringence), 3 (bubbles and inclusions), and 4 (inhomogeneity and striae). Customers used to just send optical element drawings to glass manufacturers often leading to uncertainty, overspecification, and delivery problems. The raw glass standard ISO 12123 of 2010 allows direct addressing of raw glass specifications. Harmonizing ISO 10110 with ISO 12123 and progress in inspection methods require updating of the material specifying parts. A new part 18 containing all properties is under preparation and is meant to replace parts 2–4. ISO 12123 will be amended by introducing definitions for relative partial dispersions and reference normal lines and grade denominations for tolerance ranges. The working draft ISO/WD 10110 part 18 extends indication possibilities to allow relating to ISO 12123 while ensuring backward compatibility. Default optical glass quality and direct specification of raw glass simplify tolerancing considerably. Annexes support selection of appropriate quality classes referring to optical element size categories. Test and inspection standards on chemical resistances, hardness, stress birefringence, and optical homogeneity will be maintained. Standards for water resistance, refractive index, and striae inspection are being prepared.

scholarly journals Dependence of the Distribution and Structure of the White Mulberry (Morus alba) Population in Wrocław on the Intensity of Anthropopressure and Thermal Conditions

2022 ◽  
Vol 19 (2) ◽  
pp. 838
Author(s):  
Katarzyna Blitek ◽  
Daniel Pruchniewicz ◽  
Przemysław Bąbelewski ◽  
Marta Czaplicka-Pędzich ◽  
Marcin Kubus
Keyword(s):  
Alien Species ◽  
Urban Areas ◽  
Thermal Conditions ◽  
Morus Alba ◽  
White Mulberry ◽  
Selection Of Species ◽  
The Relationship ◽  
The City ◽  
Selection Of ◽  
Size And Structure

The selection of species which show the highest possible tolerance to negative habitat conditions, also among plants of foreign origin, is a pressing issue. One of the species we would like to recommend for planting in urban areas is the white mulberry species (Morus alba) due to both its outstanding adaptability and its ecosystem services. There are no reliable studies on the distribution of this species in urbanized areas in Poland, nor sufficient analyses of the methods of its renewal, both deliberate and spontaneous spread through self-seeding. Collecting data on the population of an alien species within individual regions and forecasting potential changes in the population’s size and structure, as well as its possible impacts on other organisms, is one of the basic measures to reduce biological invasions, which is one of the six priority objectives of the European Biodiversity Strategy and an element of the Strategy on Invasive Alien Species. The aim of this study was to determine the size and structure of the white mulberry population in the city of Wrocław and to analyse the relationship between this structure and intensity of anthropopressure and thermal conditions.

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