Opal Glass Research Articles

A digital sedimentator for measuring erythrocyte sedimentation rate using a linear image sensor

A digital apparatus was fabricated to determine accurately the erythrocyte sedimentation rate (ESR) using a linear image sensor. Currently, ESR is utilized for clinical diagnosis, and in the laboratory as one of the many rheological properties of blood through the settling of red blood cells (RBCs). In this work, we aimed to measure ESR automatically using a small amount of a sample and without moving parts. The linear image sensor was placed behind a microhematocrit tube containing 36 μl of RBC suspension on a holder plate; the holder plate was fixed on an optical bench together with a tungsten lamp and an opal glass placed in front. RBC suspensions were prepared in autologous plasma with hematocrit H from 25% to 44%. The intensity profiles of transmitted light in 36 μl of RBC suspension were detected using the linear image sensor and sent to a personal computer every minute. ESR was observed at the settling interface between the plasma and RBC suspension in the profile in 1024 pixels (25 μm/pixel) along a microhematocrit tube of 25.6 mm total length for 1 h at a temperature of 37.0±0.1 °C. First, we determined the initial pixel position of the sample at the boundary with air. The boundary and the interface were defined by inflection points in the profile with 25 μm resolution. We obtained sedimentation curves that were determined by the RBC settling distance l(t) at the time t from the difference between pixel locations at the boundary and the interface. The sedimentation curves were well fitted to an empirical equation [Puccini et al., Biorheol. 14, 43 (1977)] from which we calculated the maximum sedimentation velocity smax at the time tmax. We reached tmax within 30 min at any H, and smax linearly related to the settling distance l(60) at 60 min after the start of sedimentation from 30% to 44% H with the correlation coefficient r=0.993. Thus, we may estimate conventional ESR at 1 h from smax more quickly and accurately with less effort.

Phase–mineral and chemical composition of composite samples from feed coals, bottom ashes and fly ashes at the Soma power station, Turkey

The phase–mineral and chemical composition of feed coals (FCs) and their bottom ashes (BAs) and fly ashes (FAs) produced in the Soma thermo-electric power station (TPS), Turkey, was characterized. FCs are high-ash Soma subbituminous coals abundant in moisture and Ca, and depleted in S. The inorganic composition (in decreasing order of significance) of FCs includes calcite, quartz, kaolinite, illite+muscovite, chlorite, plagioclase, gypsum, pyrite, montmorillonite, K-feldspar, dolomite, siderite, ankerite, opal, and volcanic glass. The results for 57 elements studied show that Ca>Nb>Cs>(V, Li) have significantly higher contents in FC ashes than the respective Clarke values for coal ashes. The water-soluble residues isolated from FCs include gypsum, calcite, inorganic amorphous matter, Ca–Mg–Na–K phase, and opal. These residues are enriched in Na>Se>S>B>Mg>Mo>Sr>Ca>K. The phase–mineral composition of BAs and FAs includes mainly glass, quartz, char, mullite, plagioclase, calcite, and portlandite; and, to a lesser extent, illite+muscovite, melilite, hematite, anhydrite, lime, cristobalite, kaolinite, and magnetite. Minor amounts of K-feldspar, dolomite, ankerite, Fe-spinel, gypsum, and Ca–K–Na phase also occur in BAs and FAs. FAs are enriched in inorganic matter, glass, cristobalite, mullite, Fe oxides, lime, and anhydrite, and depleted in mineral matter, char, quartz, clay minerals, melilite, portlandite, and carbonates in comparison with BAs. Only Se is significantly enriched in BAs and FAs compared to FC ashes. Most of the trace elements (in particular As, Bi, Cd, Ge, Pb, Sn, Tl, and W) are more abundant in FAs, while BAs are more enriched in Ca, Cs, Fe, Ho, Mn, P, Sc, Se and Tb. Significant percentages (11–59%) of elements initially present in FCs, namely S>Sb>Sn>Ta>Mo>Bi>Zn>Ni>Na>(Lu, Tm)>B, were emitted by stack emissions and not captured by the cleaning equipment in the Soma TPS. Some genetic features, properties, possible environmental concerns, and potential utilization directions related to FCs, BAs, and FAs are also discussed.

SINGLE-KERNEL MAIZE ANALYSIS BY NEAR-INFRARED HYPERSPECTRAL IMAGING

The objectives of this research were: (1) to develop a technique for creating calibrations to predict the constituentconcentrations of single maize kernels from near-infrared (NIR) hyperspectral image data, and (2) to evaluate the feasibilityof an NIR hyperspectral imaging spectrometer as a tool for the quality analysis of single maize kernels. Single kernels of maizewere analyzed by hyperspectral transmittance in the range of 750 to 1090 nm. The transmittance data were standardized usingan opal glass transmission standard and converted to optical absorbance units. Partial least squares (PLS) regression andprincipal components regression (PCR) were used to develop predictive calibrations for moisture and oil content using thestandardized absorbance spectra. Standard normal variate, detrending, multiplicative scatter correction, wavelengthselection by genetic algorithm, and no preprocessing were compared for their effect on model predictive performance. Themoisture calibration achieved a best standard error of cross-validation (SECV) of 1.20%, with relative performancedeterminant (RPD) of 2.74. The best oil calibration achieved an SECV of 1.38%, with an RPD of only 1.45. The performanceand subsequent analysis of the oil calibration reveal the need for improved methods of single-seed reference analysis.

Strabismic suppression depends on the amount of dissimilarity between left- and right-eye images

Suppression in strabismus is more likely to occur when the images for the left- and right-eye are similar. In this study the relationship between the depth of strabismic suppression and the amount of dissimilarity between the images was quantified. Six subjects with microstrabismus looked at two identical colorful, cartoon images via mirrors. In the middle of each screen was a circular aperture with an opal glass, which was illuminated from the back by a halogen lamp during 300 ms with a gradual on- and offset in intensity. In the circular aperture images that slightly differed in shape were presented to both eyes. The dominant eye was presented a circle, the squinting eye a circle that, in four steps, changed its shape into a square. Under each of these four conditions, the image for the dominant eye was attenuated progressively by neutral density filters. When the image for the squinting eye was perceived, the depth of the suppression was thereby measured. It was found that suppression decreased with dissimilarity of the images.

Method for Measuring Cellular Optical Absorption and Scattering Evaluated Using Dilute Cell Suspension Phantoms

The opal glass method (OGM) is a standard technique used by the ocean optics community to measure the spectral absorption coefficients of algal suspensions. We present and evaluate this method for its potential application to measurements of the inherent optical properties (optical absorption and scattering coefficients) of dilute mammalian cell suspensions, as an alternative to the integrating sphere method. In a series of controlled experiments on absorbing and scattering phantoms (Evans blue dye and polystyrene spheres 1–20 μm in diameter), separation of absorption and scattering was possible with less than 20% error in absorption coefficient estimates for particles with major scattering components in the size range of 2–5 μm.

Self-Affinity Analysis of the Fracture Surfaces of Polypropylene and Opal Glass.

In this work we report the self-affinity analysis of the fracture surfaces of a polymeric semicrystalline material and an opal glass. In the case of the plastic material, samples of isotactic polypropylene (i-PP) were prepared by varying the cooling rate from the melt; this resulted in different spherulite sizes. Samples were then broken in bend test after being immersed in liquid nitrogen. In the case of the opal glass, samples with different sizes of the opacifying particles, obtained by different thermal treatments, were broken in a punch test. In both cases the fracture surfaces were analyzed by both Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) in the contact mode. Self-affinity analysis was performed by the variable bandwidth method, covering a range of length scales spanning from a few nanometers up to ten micrometers. The roughness exponents are found to be of similar values close to ζ = 0.8 with the correlation length corresponding to the size of the spherulites in the plastic material and to the size of the opacifying particles in the opal glass. These results should be taken into account in the development of multiscale models and simulations of the fracture process of real heterogeneous materials.

Self-Affinity Analysis of the Fracture Surfaces of Polypropylene and Opal Glass.

AbstractIn this work we report the self-affinity analysis of the fracture surfaces of a polymeric semicrystalline material and an opal glass. In the case of the plastic material, samples of isotactic polypropylene (i-PP) were prepared by varying the cooling rate from the melt; this resulted in different spherulite sizes. Samples were then broken in bend test after being immersed in liquid nitrogen. In the case of the opal glass, samples with different sizes of the opacifying particles, obtained by different thermal treatments, were broken in a punch test. In both cases the fracture surfaces were analyzed by both Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) in the contact mode. Self-affinity analysis was performed by the variable bandwidth method, covering a range of length scales spanning from a few nanometers up to ten micrometers. The roughness exponents are found to be of similar values close to ζ = 0.8 with the correlation length corresponding to the size of the spherulites in the plastic material and to the size of the opacifying particles in the opal glass. These results should be taken into account in the development of multiscale models and simulations of the fracture process of real heterogeneous materials.

Changes in silicate glasses under the action of electromagnetic fields

The regularities of changes in the microhardness of sheet, container decolorized, opal, and transparent clear plate glasses under the action of constant and pulsed magnetic fields are studied. It is found that the microhardness change of a sheet glass treated with corona discharge plasma has a nonuniform character. The migration of alkalis in the sheet glass under the action of electric discharges is revealed by IR spectroscopy and the sectioning etching technique. The factors affecting the migration processes in the surface layers of sheet glasses under plasma treatment with corona and barrier discharges are determined.

Durability and cleaning of matt surface ceramic colour standards

Matt surfaced versions of the Ceramic Colour Standards are produced by CERAM Research by means of an abrasion technique applied to the normally gloss surface. These are available as an alternative to the existing matt standards made from opal glass, pressed powder and `plastic'. The existing standards have good matt surfaces but generally have a comparatively short life due to the delicate nature of the surface. This causes problems in maintaining continuity of measurement. The Ceram Research matts also have a good matt surface which, being ceramic should be durable. This paper reports the results of a series of measurements made on selected standards, which show that the standards are durable. In addition it was found that it was possible to clean the standards, returning them close to their original colour values.

Low-Temperature Electrothermal Vaporization of an 8-Quinolinolato Complex of Aluminum(III) for Sample Introduction in an Inductively Coupled Plasma Atomic Emission Spectrometric Determination of Trace Aluminum

A method based on the low-temperature electrothermal vaporization of an 8-quinolinolato complex from a tungsten boat cuvette is proposed for introducing a trace amount of aluminum present in a digested steel-making alloy or opal glass sample into an inductively coupled plasma for atomic emission spectrometric detection. The operating conditions were optimized and the effect of foreign ions was investigated. Zirconium(IV) was found to reduce the interferences from other foreign ions. The detection limit was found to be 0.12ng of aluminum and the precision in relative standard deviation for 2.0 ng of aluminum was determined to be 6.1% (n=6). The aluminum contents in some standard samples determined by the proposed method were in good agreement with the certified values.

Comparison of absolute d/O diffuse reflectance factor scales of the NRC and the PTB

A comparison of the absolute diffuse reflectance factor scales of the National Research Council (NRC, Canada) and the Physikalisch-Technische Bundesanstalt (PTB, Germany) for radiance factor measurements in the d/0 geometry was carried out in 1996. The spectral range of the comparison was 360 nm to 830 nm. The transfer standards exchanged were two matte opal glasses, one of which was similar to those used in a 1981 international comparison between the NRC, the NBS, and the PTB. The current NRC/PTB agreement is within 0,15 % from 370 nm to 830 nm, which is well within the combined relative standard uncertainties for the two laboratories. These results are generally in good agreement with those of the 1981 exchange but are significantly improved for wavelengths below 420 nm, where discrepancies of up to 0,5 % were previously reported at 390 nm. The improvement at shorter wavelengths is largely due to improvements in the uniformity of the radiance of the sphere wall and out-of-band blocking of the interference filters used for wavelength separation.

Opalescence in dental products

The aim of the investigation was to develop an opal dental glass, to characterize its microstructure and to determine the thermal properties. It was possible to develop opal glasses derived from the system SiO 2Al 2O 3K 2O. The opalescent effect is comparable to that of natural teeth. During this study it was found that two mechanisms must be controlled: the phase separation in the glass and the minimum surface crystallization at glass grain boundaries within the monolithic sample.

Stability criterion of the production technology for diffusers from flashed opal glass

Generalized data on systematic control over the density, the TCLE, and the index of inhomogeneity of colorless transparent, rose-colored and opal glasses are presented. The causes of spoilage in the production of diffusers from flashed opal glass are considered. The advantages and disadvantages of the methods for determining the physical properties of glass are described.

Catalyzed Fixation of CO2on Glass Surfaces

Some fluoride opal glass surfaces when exposed to the normal atmosphere selectively adsorb carbon dioxide and convert it to an organic compound. The organic compound was characterized and identified to be sodium formate. Probable reactions leading to the formation of the compound are proposed. These reactions have possible implications in the development of environmentally benign processes for synthesis of organic chemicals.

Increasing chemical stability of annealed hollow glassware

We will discuss the results of the authors experiments on improving the chemical stability of various types of annealed commercial glassware (i.e., after their manufacture) as well as of those in storage and use. The main points of the technique developed are as follows. A fixed quantity of the reagent is introduced into the glassware at room temperature, followed by heat treatment, during which the glass surface is leached out. For the investigation we used a variety of hollow glassware: containers (bottles, flasks, jars, etc.) from decolorized, dark-green, and brown glasses, diffusers from colorless and opal cased glasses, laboratory and high-quality vessels, ampuls from clinical glass, etc. The glass surface was leached with sulfur dioxide, hydrogen chloride and fluoride, difluorodichloromethane, difluorochloromethane, and mixtures of gases

The glass formation area in a ternary ZnOCdOSiO 2 and an Al 2O 3 sections of the quaternary ZnOCdOAl 2O 3SiO 2 system

The glass area of the ZnOCdOSiO 2 system and in a ternary section of the quaternary Al 2O 3 has been examined at 1450°C using 38 compositions. The glass-forming area covers a wide central zone of the ternary with transparent, opal and partly crystallized glasses. Transparent and opal glasses are phase-separated with homogeneously distributed droplets.

On the red coloration of saltern crystallizer ponds

To assess, respectively, the contribution of red bacteria of theHalobacterium-Haloferax-Haloarcula group and of the β-carotene-rich green algaDunaliella salina to the red colour of saltern crystallizer ponds, we studied the optical properties of the brines of NaCl-saturated saltern ponds in Eilat, Israel, and quantified the pigments present in their biota. The absorption spectrum of the brines, as measured using the opal glass method to reduce the interference by scattering, or using an integrating sphere, nearly corresponded to thein vivo absorption spectrum of bacterioruberin-containing red archaeobacteria. However, extracts of the microbial community in organic solvents were dominated by β-carotene, a pigment occurring in high concentrations in theDunaliella cells present, and bacterioruberin contributed only between 13 and 28 per cent of the total visible light absorption by the extracts. The apparent discrepancy between these results can be explained by the very small in vivo optical cross-section of β-carotene, which is densely packed in globules inside theD. salina cells.

Spectrophotometric Determination of Lead with Dithizone after Selective Separation on Polyurethane Foam Sorbents

A spectrophotometric method has been developed for determination of small amounts of lead in glass and some ceramic raw materials. The method involves selective separation of lead with 5.85 × 10−5M dithizone and 7.5 × 10−2M KCN at pH∼10 followed by elution of the complex with acetone and making it alkaline with 0.2 ml of 2.5M NH3 in a total volume of 10 ml. The method obeys Beer's law from 0.1 to 2.5 μg Pb.ml−1 at 500 nm. Correlation coefficient calculated from the linearity curve is 0.99. Interferences due tp Cu(II), Co(II), Ni (II), Zn(II), Cd(II), Mn(III) and Fe (II) have been eliminated automatically by using KCN. Effect of Fe(III) could be eliminated by extraction with MIBK prior to the separation of lead. The developed method has been standardized against National Bureau of Standards opal glass sample (NBS 91). Standard deviation of the results has been found to be ±0.0021.

In vivo chlorophyll determination in suspensions of chlorococcal algae

Summary A simple non-destructive and routine method has been developed for chlorophyll determination in vivo which is based on the measurements of absorbances of algal suspensions at 680 and 750 nm. The distorting effect of light scattering is eliminated by the Shibata's “opal glass transmission method”. The residual seeming absorbance at 750 nm must be subtracted from the value read at 680 nm. The “sieve effect” cannot be removed by optical means. Therefore, a simple mathematical correction is applied. The method is based on the in vivo absorption coefficients for suspensions of cells of different size with the shape of spheres, spheroids, ellipsoids or short cylinders. Only one linear dimension of the cell or coenobium (mean value) is needed.

Distribution of fluorine in recent marine sediments related to petrographic composition: Bransfield Strait and northwestern Weddell Sea, Antarctica

The fluorine budget of 40 marine surface sediment samples from the Atlantic sector of the Antarctic seas has been examined in order to elucidate the relationship between granulometry, mineralogy, major and minor element chemistry, and the fluorine distribution. The concentrations of total fluorine range from 243 to 800 ppm ( x ̄ = 423 ppm ). The clay and fine-silt fractions contribute 60–87% to the total concentration of fluorine. The clay fraction consists of clay minerals, detrital quartz, feldspars and an amorphous component (biogenic opal and volcanic glass shards). The fluorine concentrations in the crystalline components of Bransfield Strait and Weddell Sea sediments are 551–557 and 724–825 ppm, respectively. These variations are almost exclusively due to varying proportions of illite, which is enriched in fluorine to a considerable extent. Montmorillonite and mixed-layer clays, which carry approximately as much fluorine as illite, are present in insignificant amounts and are therefore of minor importance in the total fluorine concentration in these sediments. Biogenic opal (essentially diatom skeletons), which accounts for 3–77 wt.% of the clay fraction, contains 15 ppm fluorine. Thus, fluorine abundance in the clay fraction is negatively correlated with the content of biogenic opal. Volcanic glass shards contain 1688–3758 ppm fluorine. They comprise only up to 3 wt.% of the clay fraction and are therefore of minor relevance in the total fluorine budget in these sediments.