White Glass Research Articles

European White Glass Trade Beads as Chronological and Trade Markers

ABSTRACTEuropean explorers and traders, on their arrival in North America, found the aboriginal peoples willing to exchange furs and other goods for European-made metal objects and glass beads, the remains of which may be found at archaeological sites. Specific trade goods, including multi-coloured or curiously shaped glass beads that are visually distinctive, are used as chronological markers by archaeologists. Most of the single coloured, mainly blue or opaque white beads are very common and cannot be visually, chronologically differentiated. Non-destructive analysis (INAA) of turquoise blue or white beads from known-age archaeological sites in Ontario has revealed chemical changes in glass manufacturing compositions over time. This allows these otherwise nondescript, single coloured beads to be used as chronological and trade markers. Although the turquoise beads were always coloured by Cu, the white beads employed different opacifiers over time. First came Sn-rich beads (early to late 17th century); then Sb-rich beads (late 17th century to mid-19th century); finally As-rich beads (very late 18th century to early 20th century) and even F-whitened beads (19th century to 20th century). Within each major group, it appears that changes in glass making recipes may be found using the Na, K, Ca, Al and Cl contents. Therefore, chemical analysis of white glass trade beads may be as profitable as chemical analysis of turquoise blue trade beads in establishing chemical chronologies.

Effect of wall emissivities on radiation heat transfer in glass tank forehearths

In an earlier work, we had proposed a two-band, non-grey radiative transfer model for heat transfer in forehearths with simultaneous optically thick and thin approximations for molten glass interiors and at boundaries. Here using the same model, the radiative interaction of the top-crown and bottom-refractory walls with interior layers of shallow molten glass is studied by varying the wall emissivities. The forehearth exit temperature profiles for higher wall emissivities (0.9) show better conditioning of the glass for white flint glasses (optically thin).

Gallium colloid formation during ion implantation of glass

Data are reported on the size and depth distribution of gallium colloids formed by gallium ion implantation at energies of 50 and 60 keV, and nominal doses up to 1.1 × 10 17 ions/cm 2 into coverlip glass, float glass and white crown glass. Measurement techniques used to reveal colloid-induced changes include the wavelength dependence of optical reflectivity, transmission electron microscopy (TEM) and Rutherford backscattering (RBS). The reflectivity can be controlled by variations in ion dose, implant temperature and ion beam energy. The highest reflectivity is found after implants near 50°C and the level is extremely sensitive to the implant temperature. For controlled beam conditions, the reflectivity data are reproducible, despite there being variations in the colloid size and depth distributions as seen by TEM and RBS. The TEM data reveal that the depth distribution develops in two distinct regions, which at high concentration can precipitate into two layers of large colloids. Subsidiary experiments are reported to attempt to separate the effects of variations in the implant temperature and surface charging which influence the reflectivity, RBS and colloid formation.

Laboratory experiments on the actions of digestive enzymes

Saliva is a mixture derived from the secretions of three pairs of glands: the parotid, submaxillary and sublingual, as well as from small mucous glands scattered diffusely over the mucosa of the mouth. The amount secreted in normal adult human is between I to 1.5 litres in 24 h. The composition of saliva (pH 6.2 to 7.4) is 99.5% water and 0.5% organic and inorganic solids. The principal organic components are glycoproteins. Other proteins (eg albumin, globulin) as well as carbohydrates are also present. The principal inorganic components are calcium, sodium, potassium, magnesium and phosphorus. The amylase present in saliva hydrolyses the a(1-*4) linked Dglucose units in polysaccharides. At a pH of about 6-7 and in the presence of chloride ions, a-amylase catalyses the hydrolysis of starch to the disaccharide maltose with the intermediate formation of various dextrins. Starch and higher dextrins give a blue colour with iodine, the intermediate dextrins give a reddishbrown colour, while the lower dextrins and maltose give no reaction with iodine. Thus, the action of a-amylase can be followed by observing the time taken to reach the point at which the reaction mixture no longer gives a colour with the iodine solution, the 'achromic point'. The maltose produced in the reaction can be detected by the Benedict's test. Materials and apparatus (1) 0.1 M sodium phosphate buffer pH 6.7; (2) 0.5% starch solution. (Prepared by mixing 5 g of soluble starch with about 50 ml of the above phosphate buffer to a smooth paste which was added quantitatively to 500 ml of boiling phosphate buffer. The mixture was allowed to boil for 1 rain, cooled and made up to 1 litre with the phosphate buffer); (3) 2.5 mM iodine solution in 3% potassium iodide; (4) 1% NaCI; (5) Benedict's reagent. (Prepared by dissolving 173 g of sodium citrate and 100 g of anhydrous sodium carbonate in about 800 ml of water with heating. The solution was filtered and, with stirring, 17.3 g of copper sulphate dissolved in 100 ml water was added slowly. The final solution was made to 1 litre.); (6) 37°C water bath; (7) Boiling water bath; (8) Several white tiles and glass rods.

Ophthalmic lenses: accurately characterizing transmittance of photochromic and other common lens materials

Ophthalmic lens materials are characterized by their spectral transmittance and by derived luminous and average UV-B and UV-A transmittances. Photochromic materials, whose transmittances depend on previous and immediate radiant exposure and other environmental conditions, require special methods of spectrophotometry, which are described here. Nonphotochromic materials are characterized by customary spectrophotometry. Transmittances of seven common ophthalmic lens materials are reported (white crown glass, allyldiglycol carbonate and polycarbonate plastics, and four photochromic glasses). The transmittance spectra of sunlight-darkened photochromics are determined by extrapolation to the instant of removal from exposure by using a sequence of rapidly scanned spectra recorded at precisely timed intervals after removal. Luminous transmittances and average UV-B and UV-A transmittance of all materials tested agree well with published values.

Storage stability of sheep Samneh packaged in traditional and modern packaging materials

Samneh (Ghee, Anhydrous butter fat) was prepared from sheep butter, and packed in white glass jars, polyethylene jars, tin cans, and clay pots. Duplicates of each sample were stored under light, and dark storage conditions for a period of 30 weeks. Samples were drawn at 5‐week intervals and evaluated for the development of oxidative (peroxide value, PV), and hydrolytic (free fatty acid, FFA) types of rancidity. Results demonstrated that both storage time, and type of package have highly significant (P≤0.01) effects on the development of the two types of rancidity. They also showed that rancidity developed in the glass packed Samneh samples at higher rates than Samneh packed in other types of containers, especially under light storage conditions. The differences were less pronounced when Samneh was stored in the dark. Clay pots proved to be best packaging material for the storage of this product.

Application of an X-Ray Microdiffractometer to a State Analysis of Low-Thermal-Expansion Porcelain and Glass Ceramics

Crystalline orientation and distribution in heat-resistant porcelain and glass ceramics containing some kinds of crystals with marked thermal anisotropy were studied with an X-ray microdiffractometer equipped with a curved position sensitive proportional counter. The surface of a porcelain plate for tableware contained predominantly crystallites of β-quartz solid solution with a little orientation. The quantity of β-quartz solid solution decreased rapidly with increasing distance from the surface, and the crystallites of indialite and enstatite with relatively even orientation increased to replace that of β-quartz solid solution. Crystallites of indialite and enstatite distributed uniformly in the interior more than 200μm from the surface. It suggests a possibility of improvement in the capability against thermal shock by reducing the crystalline size and increasing the homogeneity of the crystallite distribution in the vicinity of the surface. Almost the same X-ray microdiffraction patterns of β-eucryptite were obtained from any position of a plate of transparent glass ceramics containing β-eucryptite solid solutions as its crystalline constituent. Almost the same patterns of β-spodumene were obtained regardless of the position analyzed in a plate of white glass ceramics containing β-spodumene solid solutions. These facts indicate random orientation and uniform distribution of their crystalline constituents, which explain their superior resistance against thermal shock.

The Professional Thief

THE PROFESSIONAL THIEF / Alice Denham MY MOMENT OF TRUTH, said Steadman, was when I told them how rich my family was, and I got in the fraternity. Steadman found what we photographers discover—pleasing composition. People of good wiU don't doubt great oddities if no malice is evident. Steadman wrote he'd enjoyed my exhibit. He Uved on the floor above so he dropped his card with the network logo in my box. When we talked he was so bland, I almost said no. But he had huge shimmering bluelake. eyes, like Paul Newman in four-color glossy. Sincere eyes that sunlight revealed to have layer below sparkling layer of kindness, equanimity, trusting vulnerability. His eyes spoke for him. With my new lens I could capture those eyes, with late afternoon sun slicing the retinas. Off we went on his Honda 1000 to an outdoor cafe on the towpath canal. Steadman said he was tech director on the Nightly News so we talked shop, and I criticized the way they lit the Anchor—too harsh and solemn, meaningless closeups. Closeups only for emphasis, I tell them, said Stead, but they stress Personality. That's the problem, I said, he's a nitwit and it shows up close. We laughed together. Light rippled on the brackish canal, in white wine glasses, and Stead's eyes above the checked tablecloth. Stead said TDs did okay but he had additional income of $4000 a month from circuitry he designed and patented working for IBM right out of college (MS in EE from Penn). He didn't like to teU girls this, he said, because they got greedy, but from all sources, he figured he brought in $150,000 a year at age thirty. As a poor freelancer, my brow arched and arms crossed greedily. Why don't you quit and give me your job? I smirked. Keeps me off the street, said he. At the station they know I'm working for fun and it gives me status; they treat me better. Stead said he was found, only days old, in a basket on a doorstep in South Africa with a tag attached saying, "My name is Grimm." His parents, who couldn't have children, were happy to have him, as they were rich, in import-export and emigrated here when he was five. That he became sterile through rheumatic fever as a child in Johannesburg, if it wasn't from working around radiation later. After IBM, he worked for Surplex to support the highliving of Cherry, his rich wife whom he greatly loved, who died in a car crash. He still mourned Cherry. His family was closing their Bryn Mawr and La Jolla homes and moving to Australia, to save on taxes. 34 · The Missouri Review Rich, loving, sterile meaning safe. You're a walking cliche, I said, amused. What kind of basket? Stead smiled calmly, his eyes a blue trust. What sort of apartment did this rich young man have? I suggested we have a drink there. Oddly, an efficiency like mine only pristine, antiseptic. On the glass coffeetable, a stack ofphotography magazines, a plastic flower, and a stack of racing magazines. I race bikes, he said. An unnoticeable sofa, and that was aU, like a spy's pad that told nothing, except the person's desire to conceal every aspect of personal identity. Vodka and crackers in the icebox. I eat out, he said. The sofa pulls out, he said, and reached for me. If he was reaUy sterile, that could help, ultimately, with a stranger. I was suspicious of everything but intrigued. Next evening I watched Nightly News closely when, lacking ads, they ran the Crawl. Technical Director—was not Steadman. But he was there, way down, among the Cameramen. When I confronted him, he shambled shyly and said he was trying to impress me because I was a fine wellknown photographer with my own exhibit, that he built himself up so I'd go out with him. Then there was my auburn hair like Cherry's, and my steely gaze, not at all like Cherry's. Pish taw, but shucks I fell for it. Even though he...

Evidence for magma mixing in the surge deposits of the Monte Guardia sequence, lipari

The base-surge products of the Monte Guardia sequence on Lipari contain evidence suggesting that magma mixing accompanied the main eruption. Principal data include at least two essential glass populations with discrete compositions, dominance of crystals that are incompatible with the rhyolitic glass, and contrasting quench and superheating textures in the various types of glass pryoclasts. Four distinct types of non-phenocrystic essential pyroclasts are present: vesicular white glass, non-vesicular white glass, brown devitrified clasts, and black microcrystalline clasts. The first three clast types have a uniform rhyolitic composition that is quite distinct from the alkali trachytic composition of the fourth type. These latter black microcrystaline grains have a wide range of compositions that fall in the trachyte field. Discrete crystal grains also occur as essential pyroclasts. The dominant crystal phases are augite and bytownite, with minor amounts of orthopyroxene, olivine pseudomorphed by iddingsite, magnetite, ilmenite, and sanidine. Biotite and hornblende are trace constituents. The diverse mineral assemblage and composition of the most abundant crystals suggest that their origin is different from that of the rhyolitic clasts. Pyroclast textures indicate that these magmas of different composition have been intimately mixed during eruption. The cryptocrystalline textures of the trachyte pyroclasts is due to their chilling within the rhyolitic magma. Strongly vesiculated rhyolite and glass in contact with augite and bytownite crystals suggests that these crystals were able to locally cause exsolution of volatiles. These relationships suggest a separate source for the mafic crystals, and discrete chambers for the trachytic and rhyolitic glass. The eruption model thus involves the mixing of two magmas during the interaction of the erupting materials with near-surface (sea) water.

Postpartum alopecia and zinc

Medical Journal of AustraliaVolume 1, Issue 9 p. 406-406 Letters to the Editor Postpartum alopecia and zinc John White, John White Glass Street, Essendon, Vic, 3040Search for more papers by this author John White, John White Glass Street, Essendon, Vic, 3040Search for more papers by this author First published: 01 April 1983 https://doi.org/10.5694/j.1326-5377.1983.tb136135.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume1, Issue9April 1983Pages 406-406 RelatedInformation

Influence du pH et de la lumiere sur la stabilité de quelques antioxydants

Summary Many organic molecules can be oxidized in the presence of oxygen. Light and traces of heavy metal ions catalyse the process of oxidation. The addition of a very small quantity of antioxidant to alcoholic perfumes and cosmetic bases is often made to retard auto-oxidations. Among the parameters which could influence the efficiency of an antioxidant, its intrinsic stability should be considered in the medium to be protected. This stability might conceivably be influenced by the pH, the presence of light, heavy metal ions and microorganisms. In this study we have concentrated on the role played by the first two factors. To eliminate a possible interference by the last two, analytical grades reagents together with chelators and high proof (80% v/v) hydroalcoholic solutions have been used. The antioxidants tested were: BHT, BHA, ethyl gallate, 2, carboxy-6, hydroxy, 2, 5, 7, 8, tetramethyl chroman (Trolox C(R)) and D-L-alpha-tocopherol. Solutions of 0.5 mmol/kg of each antioxidant were prepared in 80% v/v hydroalcoholic solutions and the pH adjusted with citric acid and potassium hydroxyde or hydrochloric acid. The pH extended from 2.5 to 10 and thus largely covers the pH range of cosmetic products. Of each solution, 100ml were kept in hermetically closed 125ml white glass bottles stored at room temperature (22 +/- 2 degrees C) and kept in the dark or exposed to the diffuse daylight of the laboratory. The antioxidants concentrations were determined by linear sweep voltametry on gold or glassy carbon electrodes. Significant differences in behaviour were observed. BHA and BHT are stable regardless of light and pH except at high pH (</=9). Ethyl gallate vanishes rapidly in alkaline, neutral and even weakly acid pH independently of the presence of light. Trolox C and D-L-alpha-tocopherol demonstrated a marked influence of the presence of daylight and of the pH.

Optical properties of low-temperature B 2O 3-and ZrO 2-opacified glazes

A method for the quantitative determination of the Light Scattering Capacity (LSC) of glazes is described. Using equations previously employed for milky white glasses, a method was developed for defining the LSC of low melting borozirconium glazes. Is is shown that this method may be taken as a basis for use with regard to any other glaze. The evidence indicates that an exponential dependence exists between the amount of the opacifying crystalline phase and the LSC of the investigated glazes.

Some aspects of glass control in container production

Efficient production of glass containers depends initially on feeding the machine with glass of controlled composition, weight of deviations from desired glass composition, temperature and level and indicates that the most critical variable is glass temperature. Control of glass gob temperature should start with accurate control of working end temperature to within ±4°C or better for white flint glass; control of the working end temperature can be effected by controlled heating or cooling. The desirable entrance temperature can be inferred from mathematical studies of forehearth behaviour using the 2DL model developed by Carling at the University of Sheffield. The design and operation of forehearths can also be assisted by the use of the 2DL model and the design and operation of working ends by a 3D model also developed by Carling. The paper is based on numerous measurements of temperature in working ends and forehearths in a number of factories in United Glass Limited.

Strength of thin chemtempered lenses: static load testing.

Static load tests were conducted on heat-tempered and chemtempered plano white crown glass lenses from five different optical laboratories. With both ball-on-ring and ring-on-ring loading, chemtempered lenses considerably thinner than 2.0 mm were found to be as failure resistant as 2.0-mm-thick heat-tempered lenses. A similar result was obtained previously using the drop-ball test. It is shown that the theory of brittle fracture can be used to relate the results of different tests and provides a rational basis for comparing the relative performance of chemtempered and heat-tempered lenses.

Strength of thin chemtempered lenses: drop-ball testing.

Failure heights were measured in drop-ball tests for both chemtempered and heat-tempered plano, white crown glass lenses from five different optical laboratories. It was found that (1) failure height was proportional to the square of the lens thickness, (2) chemtempered lenses substantially thinner than 2.0 mm are as resistant to breakage as 2.0-mm-thick heat-tempered lenses, and (3) a close correlation existed between results of single-drop and multiple-drop tests and between results of tests using rigid and compliant mounts.

R.D. FitzGerald - A Profile

R. D. FitzGerald, the poet, talks quietly in the big room, the slight burr in his voice, light falling on his white hair, strong brow and glasses. The house, like its neighbours on Hunters Hill, is mellow brick and stone, long since at peace with its garden; a place of clocks, dark chairs, paintings and books. 'My father, the botanist, came to Hunters Hill from Balmain in 1871; not to this house—I didn't buy this one until the Second World War—but to one not far away', FitzGerald says. 'I was born on Hunters Hill in 1902 and had nearly all my childhood here. In those days the old family houses clustered on the ridge. There was a water-bound macadam road that ran along it, with a row of pines, and paddocks on either side. This house has been here as long as I can remember—it dates from the start of the century or thereabouts."

Flow and Mixing of Powder in the Vertical-Cylinder-Type Mixer

The flow pattern and the mixing process of powder in the vertical-cylinder-type mixer were investigated using photographic observation and measurements of the concentration profile of a tracer. Furthermore, using white glass particles as a tracer, the flow pattern in the mixer was studied by the model mixer, in which glass beads were made transparent by methylbenzoate, having same refractive index with glass beads.The flows of powder varied according to the local position in the mixer. Those characteristics were shown in term of the local rate coefficient of mixing.Desirable mixing states were observed under the condition of strong shear force and large rectangular velocity gradient in powder at the front edge of the paddle. In addition, many flowing circuits and mixing zones were found at the other regions.

A New Interpretation of the Portland Vase

For three hundred years and more the meaning of the figures on the Portland Vase has been a matter for speculation of the most strange and varied character.During the first half of this century there was something of a lull, but ten years ago Professor Erika Simon, after a wide-ranging and sensitive study of all the evidence, put forward a highly ingenious theory connecting the scenes with the ancestry of Augustus and, shortly after, Professor L. Polacco embroidered it further. In 1964 Mr Denys Haynes produced the excellent little book which is on sale at the British Museum: this was reviewed by Professor H. Möbius, who had his own theory, elaborated since in a longer article; and Professor H. Biesantz has exposed the weaknesses of all the solutions, without however propounding one of his own.The wide differences of opinion among these scholars have prompted me to place on record some observations I made twenty years ago, when we first acquired the vase at the British Museum; and I shall take Mr Haynes' book as a starting-point, because it is the latest comprehensive account, and, being persuasively argued, bids fair to hold the field.However, before we begin to examine the vase in detail, a few words must be said on its technique, its date, and the circumstances in which it was made (plates I–IV, VI–VII). The technique was to make a bubble of very dark blue glass, clear but so thick that it cannot be seen through, and over it a skin of white translucent glass reaching as far upwards as the base of the neck: then to join two deep-blue glass handles from the middle of the neck to the shoulder of the vase; and, finally, using the technique of the cameo-carver, to carve, and carve away, the white glass layer in order to produce figures and landscape. The blue glass becomes the background of the scene where the white has been completely removed: where the white has been thinned but not completely removed, the blue provides suggestions of shadow and distance.

The Influence of Incandescent and Infrared Light Upon Chicks

From time to time poultry producers inquire about the cause of a peculiar eye abnormality in young chickens in which the eye appears enlarged and elongated.This condition has been described by Lauber et al. (1961) and was produced by exposing young chicks to continuous incandescent light of 3-foot candle intensity at bird level.Because poultry producers sometimes use various forms of infrared heat lamp equipment, it was desirable to determine if such equipment would cause development of the abnormal eye condition.An experiment was conducted to determine what effect light from two kinds of heat lamps as compared to light from incandescent lamps had upon chicks. Quadruplicate pens of broiler cross chicks11White Vantress male X Cobb White Rock female. equally divided for sex received light as follows:(1) 250 watt infrared heat lamps of red glass—24 hrs.;(2) 250 watt infrared heat lamps of white glass—24 hrs.;(3) 60 watt incandescent lamps—24 hrs.; …

The Estimation of Numbers of Coli Bacteria in Foods by Means of A Deep Agar Tube Technique with A Modified Violet Red Bile Agar

The author has investigated the possibilities of substituting the agar plate technique for a deep agar tube technique in estimating numbers of ooliform bacteria in foods. Especially when water bath incubation at 44°C is used for selective counting of E. coli I a tube technique would seem to offer considerable practical advantages over the ordinary Petri dish plate technique. The medium selected for the purpose is Violet Red Bile Agar. However, in order to be able to cultivate ooliform bacteria in VRB-deep agar tubes the formation of gas from fermentation of lactose must be suppressed. To achieve anaerogenic growth of ooliform bacteria the author has utilized the existing knowledge of the inhibitory effect of nitrate- and nitrite ions upon the formic acid hydrogenlyase enzyme which catalyses the decomposition by coliforms of formic acid into hydrogen and carbon dioxide. Nitrate was found preferrable to nitrite because of less inhibitory effect. The optimal concentration of nitrate in VRB Agar was determined to 0.5 % NaNO3. Flat Miller-Prickett-tubes with an inlaid white enamel glass plate were found to facilitate counting. To obtain well developed colonies with a typical zone of precipitation the agar contents of the medium was reduced to 0.9 per cent. Two series of comparative coli counts with the modified VRB-Nitrate agar in deep agar tubes against ordinary VRB-Agar in Petri dishes at 37° C and 44°C showed on the whole no statistically valid differences. The problem of small retarded colonies appearing in tube cultures and plate cultures as well, mostly when seeded with raw milk, was investigated. All of 108 such strains except two could be identified as members of the ooliform group. The selectivity of the medium was tested by plating a variety of non-ooliform organisms. Only a few strains of fecal streptococci, Proteus, Aloaligenes and Pseudomonas were capable of scanty growth, and in no instance the resulting colonies could be mistaken for colonies of ooliform bacteria.