Opal Glass Research Articles

Solar Light Radiometry Calibration Unit for a ScanPol Polarimeter of the Aerosol-UA Space Mission

The Aerosol-UA space mission will study aerosol microphysical characteristics in the Earth’s atmosphere based on the multispectral scanning polarimeter (ScanPol) and imaging polarimeter (MSIP). Both polarimeters must be precisely calibrated on the ground and in orbit to provide correct measurements. This paper considers the results of developing an experimental device for the radiometric calibration of the ScanPol. We consider the calibration unit design and operation principle to form a luminous flux with unchanged or well-predicted characteristics in a specified direction. The construction of the radiometric calibration unit is based on a sun-illuminated reflective diffuser made from the white opal glass MS20. We evaluated the scattering and polarization characteristics of the diffuser in laboratory experiments at a wide range of wavelengths. The results suggest that the polarization properties of the diffuser are negligible. The diffuser scattering parameters are close to Lambertian for illuminance conditions, which is necessary for radiometric calibration. The calibration unit was manufactured and tested during field observations of solar radiation. The results will be used for its improvement, mainly to reduce the observed stray scattered radiation entering the telescopes of the ScanPol polarization state analyzer.

Novel extraction protocol for evaluating abundances and structural features of amorphous SiO2

Spectral data from satellite and rover missions on Mars identified significant abundances of amorphous phases in most samples analyzed, and SiO2 is the principal amorphous constituent in the Gale crater. Identifying and quantifying these short-range ordered, highly reactive phases is challenging but necessary to gain insight into the evolution of these materials. Terrestrial analogs are frequently employed to allow detailed analyses that cannot be performed on Martian samples. Historically, chemical extraction techniques have been extensively used to characterize amorphous materials in terrestrial soils, but most automated systems are complex, expensive, and limited to analyzing a single sample at one time. This study aims to develop a cost-effective apparatus that will allow latitude in choosing an extractant, process several samples simultaneously, enable rapid sampling over time without interruption and provide the resolution for quantitative differentiation of rapidly dissolving SiO2(a) phases in natural samples. Dissolution rates as a function of time were used as input for kinetic models to estimate the abundances of amorphous phases. When 2 M Na2CO3 is used as the extractant, dissolution rates differ significantly between secondary phases such as opal and primary glass phases. A stronger base, NaOH, is necessary for the complete dissolution of basaltic glass. Palagonitic tuffs from Iceland (proposed analogs of Martian soils) with >90% (w/w) amorphous composition were analyzed with 2 M Na2CO3 in the proposed apparatus, and both primary glass and secondary SiO2 appear to be present. Using the kinetic model of the dissolution, the palagonitic tuff has a composition of approximately 25% (w/w) of a rapidly reacting amorphous phase and 13% (w/w) of the slower reacting glass-like phase. The proposed high-efficiency analytical method can be applied to screen multiple terrestrial analogs and archive dissolution kinetics of many standard amorphous minerals. Although this paper focuses on extracting SiO2(a), the same setup can be applied to study time-based dissolution reactions using other extractants such as ammonium oxalate oxalic acid.

Up-cycling of ‘unrecyclable’ glasses in glass-based foams by weak alkali-activation, gel casting and low-temperature sintering

A significant amount of glasses is landfilled because mainstream recycling solutions do not address the articles of specific chemical compositions, including opal glass and glass fibers residues. This manuscript suggests the up-cycling of these glasses through the production of highly porous glass foams. Fine glass powders were dispersed in weakly alkaline solutions, which were foamed by the combination of surfactant addition and intensive mechanical stirring. The cellular structures were stabilized first by the gelation of suspensions, upon drying, then by viscous flow sintering at 700–800 °C, for 10–60 min. The foams based on glass fibers reached an excellent strength-to-density ratio, due to the formation of closed cells and partial crystallization. The foams made from opal glass maintained a particularly uniform open porosity, and importantly, also retained the volatile and toxic fluorine due to the rapid, low-temperature sintering.

Accounting for polarization–related effects in the measurement of the bidirectional reflectance distribution function

When measuring the Bidirectional Reflectance Distribution Function (BRDF) to characterize typical materials, the effect of the polarization of the light source or the dependence of the detector on the polarization is not usually considered, even though many studies have proven their impact in the uncertainty of the BRDF of most materials, including diffuse reflectance standards. A methodology to assess polarization-related effects proposed by other authors has been tested in this work for the measurement of the BRDF of four typical materials used for realizing white diffuse reflectance standards (ceramic tile, barium sulfate, Spectralon and Russian opal glass). Relative systematic error due to polarizing conditions is calculated as a combination of the instrument polarization bias and sample-based coefficients, and the impact of the proposed methodology on the uncertainty is discussed.

An Approach to Evaluate Exhibition Lighting Alternatives: The Case of Museum of Palace Collections

Purpose Museums collect, preserve, analyse, and exhibit works of art and historical values. There are numerous publications that offer guidance on museum lighting to balance exhibition and preservation requirements. Some guidelines such as the way of control of illuminance on three-dimensional artefacts, the acceptable illuminance uniformity, and the limiting values for direct glare are missing in literature on museum lighting. The aim of this study is to suggest limiting values for the mentioned lighting requirements, describe the way of lighting control on 3D objects, and to present an approach to evaluate different lighting alternatives in terms of conservation, accurate perception of artworks, and energy consumption. Design/Methodology/Approach The evaluation of various lighting alternatives was carried out by reference to the Museum of Palace Collections. The lighting alternatives that can be applied in the exhibition hall of the museum were investigated in the first phase of the study. Twelve lighting arrangement alternatives have been design ed and modelled by means of DIALux lighting software and the results were obtained in terms of preservation, lighting design criteria, and energy consumption. An approach has been developed in which all considered criteria were assessed separately. The results of twelve lighting arrangements were compared according to the presented approach. The number of lighting design criteria that met the requirements and their degree of fulfilment were considered in comparison. Subsequently, the optimal lighting alternatives were determined. Findings The results acquired in the twelve arrangements designed via the lighting program were compared with respect to illuminance level and uniformity, direct glare, reflected glare, shadow properties, perceptibility of the hall, and energy efficiency. Taking into account all the mentioned criteria the optimum lighting arrangements for the conditions of this study were determined as ‘indirect general lighting and showcase lighting with horizontal linear luminaire behind the upper metal profile’, followed by ‘indirect general lighting and showcase lighting with horizontal linear lamp behind the opal glass ’. Research Limitations/Implications So as to limit the conditions of the study, the existing showcase types and the exhibition design were kept constant. It is obvious that more lighting alternatives can be created by considering other types of showcases and exhibition design in addition to the existing ones. Practical Implications The evaluation process proposed in this study and discussed using the Museum of Palace Collections as an example can be followed to make the most rational decision regarding the illumination of other exhibition halls. Social Implications One of the main objectives of museum lighting is to assure the visitors perceive the properties of exhibited objects comfortably and completely. The perceptibility of the exhibition hall itself can also be important especially if it has historical value and/or exceptional architecture. Rational decisions for artificial lighting ensure that the hall and the artefacts displayed within it are fully and comfortably perceived and consequently visitors can benefit as much as possible from the exhibition. Originality/Value In this study, some missing guidelines for museum lighting are proposed and an approach is presented to evaluate possible different lighting alternatives for exhibition halls. Finally, the importance of simultaneous architectural-, interior-, lighting- and display design is emphasized.

Lower airways and lungs affection in coronavirus infection covid-19 among children and adults: similarities and differences (review of literature)

The review presents the data of actual publications for 2019-2020 regarding the course of a new coronavirus infection COVID-19 in children and adults. The features of a new coronavirus SARS-CoV-2, the causes of its tropism to human respiratory system are discussed. The questions of clinical and roentgenological manifestations of lung affection in COVID-19 among children and adults are described in details. The adult COVID-19 is characterized by the presence of clinical symptoms of acute respiratory viral infection: elevation of temperature ( 90 %), cough (dry or with small amount of sputum) in 80% of cases, dyspnea (55 %), fatigability (44 %), sense of stiffness in chest ( 20 %). The most severe dyspnea is being developed by the days 68 from the moment of falling ill. Separately, the peculiar features of computed tomography of the lungs in children and adults with COVID-19 are discussed. The typical signs for CT-picture of the lungs in children with COVID-19 infection and pneumonia are bilateral affection, infiltration with a typical surrounding aureole the sign of halo, the symptom of opal glass with predominantly peripheral localization and often in combination with elevated procalcitonin level. The cases of pneumonias in newborns and children of the first year of life with COVID-19 infection are considered in the paper. A clinical case with roentgenograms of thoracic organs and results of computed tomography accompanying is presented as an illustration. The high-risk groups of complicated COVID-19 course can include children with chronic bronchopulmonary diseases, patients with immune deficiencies, hemodynamically significant heart failures and chronic renal disease.

Surface roughness affects early stages of silica scale formation more strongly than chemical and structural properties of the substrate

Precipitation of amorphous silica (SiO2) in geothermal power plants has been shown to occur via homogeneous nucleation in the separated water as well as heterogeneous nucleation on pre-existing surfaces. While the factors facilitating homogeneous nucleation are well known, the effect of surface properties on the heterogeneous pathway are less well understood. We investigated the precipitation of amorphous silica onto different surfaces by placing coupons of opal (= mirroring previously deposited silica), volcanic glass (= common reservoir rocks) and corrosion-resistant carbon steel (= geothermal pipelines) inside the pipelines of the Hellisheiði power plant (SW-Iceland) where they were in contact with a silica-supersaturated geothermal liquid (800 ppm SiO2, 60–120 °C) for up to 10 weeks. Our results showed that the similarities in chemical composition and structure of opal and volcanic glass to the amorphous silica were less important in facilitating nucleation than the rough surface of the carbon steel. However, once the nuclei had formed, their growth was independent of the surface material and only controlled by deployment length, temperature and the concentration of monomeric silica in the separated water. Thus, over time a continuous, botryoidal silica layer formed on all coupons. This suggests that surface properties are not crucial in developing better mitigation strategies against amorphous silica scaling.

Deviation of white diffuse reflectance standards from perfect reflecting diffuser at visible and near-infrared spectral ranges

The assumption that the reflectance of white diffuse reflectance standards is identical to that of the perfect reflecting diffuser (PRD) allows these standards to be used to characterize reflectance or radiance factors of any surface at any irradiation/collection geometry simply by comparison. However, this assumption is only true within certain limits, and, for some applications, requirements may be out of those limits. PTB and IO-CSIC have studied the variation of the reflectance with respect to the bidirectional geometry for the four most typical white diffuse materials (barium sulfate, opal glass, ceramic and Spectralon), at in- and out-of plane geometries and at spectral range from 380 nm to 1700 nm. We have defined descriptors in order to more clearly quantify the spectral reflectance variation with the bidirectional geometries. The values obtained for these descriptors have been separately presented for the visible and near-infrared spectral ranges. In both spectral ranges, deviations of white diffuse reflectance standards with respect to the PRD were found, regarding both Lambertian behaviour and spectral constancy. The observed deviation from the BRDF is in general very large for high incidence and collection angles (reaching in many cases 20%). Therefore, it is not possible to assume Lambertianity in standards at those geometries when calibrating measuring systems.

Effect of CaO on Phase Separation and Properties in Na2O-CaO-SiO2-P2O5 Opaque Glass

In the Na2O-CaO-SiO2-P2O5 opaque glass system, the effects of CaO on the phase separation and properties were investigated by means of SEM, XRD, UV-VIS Spectro Photometer, Thermal dilatometer, etc. The results showed the size of the second phases enriched with phosphate became smaller from 200nm to 80nm with the increase of CaO concentration. CaO had clear influence on the transmittance of opal glass, and the glass was changed into semi opaque when the amount of CaO was 12%. It also affected the crystallization of the glass samples, especially in crystal peak intensity of the Na3Ca6(PO4)5 and Zn2P2O7. the coefficient of thermal expansion of sample was reduced but the density increased with the increase of CaO concentration. Results showed that Calcium ions in Na2O-CaO-SiO2-P2O5 system was good to bind with the P ions and boost the separation of the second phase and the crystallization.

Possibilities of x-ray computer densitometry in diagnosis of occupational hypersensitivity pneumonitis

The article presents results of assessing lung parenchyma density within X-ray diagnostic pattern “Opal glass” in patients with changes characteristic for occupational hypersensitivity pneumonitis(60 patients) and interstitial pneumonia (65 patients of reference group) vs. reference group (70 individuals), by modified method of X-ray computer tomography of high resolution. Quantitative characteristics as native parameter (HU units), density gradient (IDG), with consideration of homogeneity degree of the evaluated zone by SD value enabled considerable objectification of the changes direction in diagnostic monitoring of the studied lung disorders.

Report of the key-comparison of spectral diffuse reflectance (EURAMET.PR-K5) (Ref. 619)

This report details the final results of the EURAMET comparison on regular spectral transmittance carried out between 2006 and 2016.The aim of this comparison was to check the agreement of measurement of the spectral diffuse reflectance among participants, using the measurement geometry of d/0 or 0/d in the wavelength range of 360 nm to 780 nm at 20 nm increment. We used a star type comparison: first the participants sent their samples to the pilot, than the pilot measured all the samples of the participants and sent them back. The participants measured the samples and sent them to the pilot for control measurement.Six standards were used as reference standards in order to maintain the scale during the comparison. These were three samples of BCR-406 opal glasses (BCR 30506; BCR 30303; BCR 30704), an MC20 Russian opal glass (MC 4777) and two samples made of pressed halon (polytetrafluoroethylene) powder (halon 2007A; halon 2007C). These six samples were designated as the Comparison reference standards. The diffuse reflectance was initially measured on the OMH (BFKH) absolute reflectometer.The link to the CCPR-K5 results was BFKH, and the check on BFKH was the PTB results who also participated in the CCPR-K5 comparison.The participants were GUM, INM, LNE, METAS, BFKH, PTB, SP.Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Contactless Visualization of Latent Fingerprints on Nonporous Curved Surfaces of Circular Cross Section-A Statistical Evaluation on the Materials as Plane Mirror.

A new contactless technique for latent fingerprint visualization on nonporous curved surfaces of circular cross section was introduced by Low et al. (1). The technique utilizes a plane mirror to convey the light rays toward the inspected surfaces for latent fingerprint visualization. This research activity came up as an extension of the previous study which utilized an aluminum plate as the plane mirror to illuminate the inspected surfaces. Dulling spray was used to increase the diffuse component of the reflective aluminum plate. However, the amount of dulling spray will affect the uniformity of the illumination on the inspected curved surfaces. In this study, a study on the new materials for the plane mirror was carried out. Coated aluminum, opal, and ground glass diffusers were selected as the new materials. The performance of the new materials was compared to the aluminum based on the quality of the captured images on various nonporous cylindrical surfaces. A statistical approach known as randomized complete block design was used to design the experiment. The quality of the captured images was obtained using Spectral Image Validation and Verification. Two-way analysis of variance and Fisher's least significant difference test were used to analyze the quality of the images. From the results of the statistical analysis, coated aluminum has the best performance compared to aluminum, opal, and ground glass diffusers.

Corrosion Behavior of Fluoride-free Phosphate Opal Glass in Hydrochloric Acid Solutions

High quality of opal glass container were more and more popular in the last few years, so their safety and chemical stability was paid more attention on. The corrosion behavior of hydrochloric acid on the phosphate opal glass was studied in the paper. In order to investigate the effect of acid on the opal glass, the different parameters such as concentration, temperature as a function of the time was researched. The results showed that opal glass exhibited good chemical stability, and the migration of alkali ion dominated the degradation of opal glass treated in hydrochloric acid on. The main glass network was stable, but the separated second phase would boost the deterioration of corrosion behavior, and results showed that the degraded velocity of P was twice as fast as that of B and Si.

Atomic mobility in a ternary liquid Ga–In–Sn alloy of the eutectic composition

The nuclear spin–lattice relaxation and Knight shift of 71Ga, 69Ga, and 115In nuclei in a ternary liquid gallium–indium–tin alloy of the eutectic composition, which was introduced into pores of an opal matrix and porous glasses with pore sizes of 18 and 7 nm, have been investigated and compared with those for the bulk melt. It has been found that longitudinal relaxation is accelerated and the Knight shift is decreased, depending on the size of pores. The correlation time of the atomic motion has been calculated for the nanostructured melt in porous matrices. It has been shown that the atomic mobility in the melt decreases with decreasing size of pores in the glasses.

利用乳白玻璃测量日冕仪平场的方法

利用乳白玻璃测量日冕仪平场的方法

Dr. S. Donald (Don) Stookey (1915–2014): Pioneering Researcher and Adventurer

Don Stookey was a special person by any measure: an unassuming optimist, eminent scientist and inventor, adventurer, and a beloved family man. Don Stookey, the father of glass-ceramics, was a pioneer in inducing and understanding internal nucleation phenomena in glass. His early work on dense opal glasses and photosensitive precipitation of gold and silver in glass led to an amazing series of inventions: Fotalite®, a photosensitive opal, chemically machined Fotoform® and Fotoceram®, and TiO2-nucleated Pyroceram™ products including missile nosecones and oven-proof cookware. He received a basic patent on glass-ceramics which was contested and affirmed in court. Don was able to demonstrate a clear photochromic glass that showed reversible darkening for thousands of cycles. This material became a fixture in the ophthalmic industry. He went on to invent a full-color polychromatic glass capable of yielding a permanent patterned and monolithic stained glass. In his life outside science, Don chaired an interfaith group that founded a home for the elderly in Corning. He was also a wilderness enthusiast, surviving a plane crash in the Arctic and two boat capsizings. Even In his later years, he continued fishing off the coast of Florida and on Lake Ontario, and went solo on a trip to the Patagonian Andes.

Fluorine Assessment of Igneous Rocks by Neutron Activation Analysis

The main goal of the current study was to determine the fluorine in the rock samples coal (SARM-18, SARM-19, and SARM-20), opal glass NBS91 and phosphate rock NBS694 using neutron activation analysis. Neutrons energy of 14 MeV used for irradiation was produced by bombardment of a water-cooled titanium tri-tide target with a beam of deuterons accelerated to a potential of 350 KV to develop a neutron flux (108 n⋅cm-2⋅s-1) on the sample at the neutron generator in the ECN (Netherlands Energy Research Foundation) Petten. This new approach contributes to the existing knowledge of fluorine measurement by the coincidence channels investigation of the positron energy with respect to decay time for each radionuclide element. The present study was designed to determine the fluorine by fast neutron through the reaction of F19 (n, 2n) F18. Interference was treated by irradiating the standard of these elements and reasonable selection of the decay time between the end of irradiation and beginning of counting time. The results of this method indicate that the concentration of fluorine is agreed fairly with literatures.

LED diffuser용 green color 유백유리에 있어서 산화철 함량에 따른 특성

Translucent green colored opal glass was fabricated to substitute polycarbonate diffuser of LED lighting in order to solve the durability problem. Batch materials of green colored opal glass with the composition of calcium phosphate for opacifier and iron oxide for colorant were made and melted at 1550 C. As the results, translucent green colored opal glass was obtaind, which had excellent optical properties compare with nomal color glass for the diffuser of LED lighting, with no dazzling from direct light by high haze value over 90 % and low parallel transmittance value about 1 %. Therefore, it is concluded that this translucent green colored opal glass can be used for the glass diffuser materials of LED lighting with high heat resistance and high durability to substitute polycarbonate diffuser.

Bidirectional reflectance distribution function of diffuse reflectance standards around the retro-reflection direction

The increase in the bidirectional reflectance distribution function around the retro-reflection direction was characterized for four common diffuse standard reflectance materials: Spectralon, matte white Russian opal glass, matte white ceramic standard and pressed barium sulphate (BaSO4) powder. The characterized increase or surge is high enough to be considered in low-uncertainty reflectance factor measurements, where the values are usually extrapolated around that direction due to instrumental limitations. In order to make the corrections for this surge, the coherent backscattering of light model and a much simpler exponential function were fitted to the measurements.

Devitrification and Phase Separation of Zinc Borosilicate Glasses in the Presence of MgO, P2O5, and ZrO2

A base glass composition which undergoes phase separation was chosen in the system Na2O‐ZnO‐B2O3‐SiO2. Spontaneous and reheat‐treatment opal glasses were synthesized by addition of different amounts of oxides such as P2O5 and ZrO2. To clarify devitrification, visible spectroscopy was performed for all samples. Reheat‐treated samples showed Tyndall effect in low temperatures, while they were completely opacified after soaking in 800°C for 3 h. P2O5‐or ZrO2‐containing samples opacified spontaneously. The mechanism of opacification in glasses containing the MgO and ZrO2 was partial crystallization, while in the mechanism of P2O5‐bearing one was liquid–liquid phase separation.