Measurement of near-UV irradiance taking into consideration reciprocity law failure for irradiated materials.

Abstract After the significant work of Zagier on the traces of singular moduli, Jeon, Kang and Kim showed that the Galois traces of real-valued class invariants given in terms of the singular values of the classical Weber functions can be identified with the Fourier coefficients of weakly holomorphic modular forms of weight 3/2 on the congruence subgroups of higher genus by using the Bruinier-Funke modular traces. Extending their work, we construct real-valued class invariants by using the singular values of the generalized Weber functions of level 5 and prove that their Galois traces are Fourier coefficients of a harmonic weak Maass form of weight 3/2 by using Shimura’s reciprocity law.

Download Full-text

UV Irradiance Enhancements by Scattering of Solar Radiation from Clouds

Atmosphere ◽

10.3390/atmos6081211 ◽

2015 ◽

Vol 6 (8) ◽

pp. 1211-1228 ◽

Cited By ~ 23

Author(s):

Uwe Feister ◽

Nathalie Cabrol ◽

Donat Häder

Keyword(s):

Solar Radiation ◽

Uv Irradiance

Download Full-text

Analysis of the holographic reciprocity law for dichromated gelatin

Applied Optics ◽

10.1364/ao.31.003200 ◽

1992 ◽

Vol 31 (17) ◽

pp. 3200 ◽

Cited By ~ 1

Author(s):

I. Pascual ◽

A. Beléndez ◽

A. Fimia

Keyword(s):

Reciprocity Law ◽

Dichromated Gelatin

Download Full-text

Applicability of Exposure Reciprocity Law for Fast Polymerization of Restorative Composites Containing Various Photoinitiating Systems

Operative Dentistry ◽

10.2341/20-112-l ◽

2021 ◽

Author(s):

A Tichy ◽

P Bradna

Keyword(s):

High Power ◽

Irradiation Time ◽

Spectral Characteristics ◽

Degree Of Polymerization ◽

High Irradiance ◽

Bottom Surface ◽

Surface Microhardness ◽

Radiant Exposure ◽

Reciprocity Law ◽

Restorative Composites

SUMMARY Objectives: The exposure reciprocity law (ERL) has been used to calculate the optimal irradiation time of dental composites. This study examined the applicability of ERL for fast polymerization of restorative composites containing various photoinitiating systems using a high-power multi-peak light-emitting diode (LED) lamp. Methods: Three commercial composites differing in photoinitiating systems were tested: Filtek Ultimate Universal Restorative (FU) with a camphorquinone-amine (CQ-A) photoinitiating system, Tetric EvoCeram (TEC) with CQ-A and (2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and Estelite Σ Quick (ESQ) with CQ and a radical amplified photopolymerization (RAP) initiator. Specimens 2-mm thick were polymerized using a high-power multipeak LED lamp (Valo) at 3 pairs of radiant exposures (referred to as low, moderate, and high) ranging from 15.8–26.7 J/cm2. They were achieved by different combinations of irradiation time (5–20 seconds) and irradiance (1300–2980 mW/cm2) as determined with a calibrated spectrometer. Knoop microhardness was measured 1, 24, and 168 hours after polymerization on specimen top (irradiated) and bottom surfaces to characterize the degree of polymerization. The results were statistically analyzed using a three-way analysis of variance and Tukey’s post hoc tests, α = 0.05. Results: Microhardness increased with radiant exposure and except for ESQ, top-surface microhardness was significantly higher than that on bottom surfaces. Combinations of high irradiance and short irradiation time significantly increased the top-surface microhardness of TEC at low and moderate radiant exposures, and the bottom-surface microhardness of FU at a low radiant exposure. In contrast, the microhardness of ESQ on both surfaces at high radiant exposure increased significantly when low irradiance and long irradiation time were used. With all tested composites, bottom-surface microhardness obtained at low radiant exposure was below 80% of the maximum top-surface microhardness, indicating insufficient polymerization. Conclusion: Combinations of irradiance and irradiation time had a significant effect on microhardness, which was affected by photoinitiators and the optical properties of composites as well as spectral characteristics of the polymerization lamp. Therefore, ERL cannot be universally applied for the calculation of optimal composite irradiation time. Despite high irradiance, fast polymerization led to insufficient bottom-surface microhardness, suggesting the necessity to also characterize the degree of polymerization on the bottom surfaces of composite increments when assessing the validity of ERL.

Download Full-text

Estimating cloud optical thickness and associated surface UV irradiance from SEVIRI by implementing a semi-analytical cloud retrieval algorithm

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-7961-2012 ◽

2012 ◽

Vol 12 (17) ◽

pp. 7961-7975 ◽

Cited By ~ 7

Author(s):

P. Pandey ◽

K. De Ridder ◽

D. Gillotay ◽

N. P. M. van Lipzig

Keyword(s):

Optical Thickness ◽

Correlation Coefficients ◽

Retrieval Algorithm ◽

Satellite Mission ◽

Spectral Bands ◽

Uv Irradiance ◽

Intercomparison Exercises ◽

Cloud Optical Thickness ◽

Mean Square Difference ◽

Good Agreement

Abstract. In this paper, we describe the implementation of the Semi-Analytical Cloud Retrieval Algorithm (SACURA), to obtain scaled cloud optical thickness (SCOT) from satellite imagery acquired with the SEVIRI instrument and surface UV irradiance levels. In estimation of SCOT particular care is given to the proper specification of the background (i.e. cloud-free) spectral albedo and the retrieval of the cloud water phase from reflectance ratios in SEVIRI's 0.6 μm and 1.6 μm spectral bands. The SACURA scheme is then applied to daytime SEVIRI imagery over Europe, for the month of June 2006, at 15-min time increments. The resulting SCOT fields are compared with values obtained by the CloudSat experimental satellite mission, yielding a negligible bias, correlation coefficients ranging from 0.51 to 0.78, and a root mean square difference of 1 to 2 SCOT increments. These findings compare favourably to results from similar intercomparison exercises reported in the literature. Based on the retrieved SCOT from SEVIRI and radiative transfer modelling approach, simple parameterisations are proposed to estimate the surface UV-A and UV-B irradiance. The validation of the modelled UV-A and UV-B irradiance against the measurements over two Belgian stations, Redu and Ostend, indicate good agreement with the high correlation, index of agreement and low bias. The SCOT fields estimated by implementing SACURA on imagery from geostationary satellite are reliable and its impact on surface UV irradiance levels is well produced.

Download Full-text

Instrument SectionA Special Sensitometer for the Study of the Photographic Reciprocity Law*

Journal of the Optical Society of America ◽

10.1364/josa.7.000305 ◽

1923 ◽

Vol 7 (4) ◽

pp. 305 ◽

Cited By ~ 14

Author(s):

Loyd A. Jones

Keyword(s):

Reciprocity Law

Download Full-text

Principal Possibility of the Successful Nowcast and Short-Term Forecast in the Middle Atmosphere Based on the Observed UV Irradiance

International Journal of Geophysics ◽

10.1155/2012/298431 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7

Author(s):

T. Egorova ◽

E. Rozanov ◽

A. V. Shapiro ◽

W. Schmutz

Keyword(s):

Climate Model ◽

Middle Atmosphere ◽

Satellite Measurements ◽

Short Term ◽

Short Term Forecast ◽

Atmospheric Species ◽

Term Forecast ◽

Uv Irradiance ◽

Solar Uv ◽

Solar Uv Irradiance

We have applied chemistry-climate model (CCM) SOCOL to simulate the distribution of the temperature and gas species in the upper stratosphere and mesosphere. As an input for the simulation, we employ daily spectral solar UV irradiance measured by SUSIM instrument onboard UARS satellite in January 1992. We have carried out an ensemble of nine 1-month long simulations using slightly different initial states of the atmosphere. We have compared the obtained time evolution of the simulated species and temperature with available satellite measurements. The obtained results allowed us to define the areas where the nowcast and short-term forecast of the atmospheric species with CCM SOCOL could be successful.

Download Full-text