Glass marble

Methyl fluoroacetate.1 Methyl chloroacetate (108-5 g., 1 mol.) and neutral anhydrous potassium fluoride (70 g., 1-2 mol.) are mixed and heated (with glass marbles) in an inclined rotating autoclave at a... 

The experiments were conducted in "solubility tubes" each containing two glass marbles. The tubes were rotated at 25.00 0.02°C to keep the material finely ground. 

Continuous textile fibers are usually made by drawing molten glass though a bushing with many fine holes. In Fig. 2.20 glass marbles of controlled composition are fed into the melting pot, and primary filaments of glass are pulled into the jet flame. Typically, uniform-diameter fibers of between 4 and 20 micrometers are drawn at speeds in excess of 5000 feet per minute. 

Tin(lV) oxide occurs in nature as mineral cassiterite. It is used to make specialty glasses, in manufacturing enamels and pottery, for pohshing glass marbles, metals and decorative stones, as a mordant in dyeing and printing textiles, in perfumes, and nail pohshes. 

The difference between macroscopic and microscopic objects is clear from everyday experience. For example, a glass marble will sink rapidly in water however, if we grind it into snb-micron-sized particles, these will float or disperse freely in water, prodncing a visibly clondy soln-tion , which can remain stable for honrs or days. In this process we have, in fact, prodnced a colloidal dispersion or solution. This dispersion of one (finely divided or microscopic) phase in another is quite different from the molecular mixtures or true solutions formed when we dissolve ethanol or common salt in water. Microscopic particles of one phase dispersed in another are generally called colloidal solutions or dispersions. Both nature and industry have found many uses for this type of solution. We will see later that the properties of colloidal solu-... 

Add 50 pi sample (homogenate) and 200 pi 33% KOH to a test tube. Use high test tubes because of concentrated sulfuric acid. Boil for 20 min with the tubes covered with a glass marble. After cooling on ice-H20 add 1.75 ml H20. 

Care must be taken to exclude air bubbles when weighing in water, and this is helped if a trace of detergent is added and/or the test piece quickly dipped in ethanol before weighing. If the rubber is less dense than water, then a sinker must be used in the same manner as for density measurements (see Chapter 7). The test piece is then immersed in the test liquid for the chosen time at the chosen temperature. At least 15 times the test piece volume of liquid should be used and care must be taken to ensure that the rubber is exposed on all sides to the liquid. This can be done by suspending the test pieces on wires or it is satisfactory to rest them on glass marbles. 

Transfer all BCA-containing reaction mixtures to an 80°C water bath to initiate color development. Cover each tube with a glass marble, Parafilm, or other suitable covering to minimize evaporation, and leave tubes in bath for 30 min. 

Place glass marbles on top of the tubes to prevent contamination of the samples by condensation. 

Dark brown or amber glass bottles are best for storing developers. Always fill the bottle to the top in order to prevent oxidation. This can be achieved through the addition of glass marbles that take up extra space. However, do not use glass marbles with developers with high acid or alkali content (Appendix 2 Chemicals Dos and Don ts). 

A wad of glass wool in the bottom of a glass funnel may sometimes be used to filter corrosive liquids. Another method which can be used in separating crystals from a corrosive liquid consists in putting a glass marble into a funnel. The crystals form a mat in the small space between the marble and the sides of the funnel and the liquid can be removed by suction. 

A boy decides to place his glass marbles in an oven at 200°C. The diameter of the marbles is 15 mm. After a while he takes them from the oven and places them in room air at 20°C to cool. The convection heat-transfer coefficient is approximately 14 W/m2 °C. Calculate the time the boy must wait until the center temperature of the marbles reaches 35°C. 

Incubate the five tubes at 40° for exactly 15 min, and then add 4 mL of Neocuproine Solution A to tubes 1, 2, 4, and 5. Add 4 mL of Neocuproine Solution B to all five tubes, and cap each with a suitably sized glass marble. 

The samples are heated in a dry block at 170°C until the sample is completely dry. A 2 ml aliquot of fuming nitric acid is carefully added using a glass calibrated pipette, the tubes covered with a large glass marble to prevent evaporation and the sample is heated at 170°C to digest the sample. After 20 min the marble is removed, and the heating continued until the nitric acid has completely evaporated. 

In the older marble melt process glass marbles manufactured separately are melted in the spinning jets. The marble melt process is only used when very fine fiber diameters are required or when special glass compositions are being used. The rod drawing process is less important. In this process glass rods are fed at a constant speed into the melting zone and fibers are drawn continuously onto a spool. 

E-giass powders were obtained by crushing E-glass marbles. The powders were screened and the portions retained on 48-, 65-,... 

To illustrate the problem for the product developer, one only has to enumerate the soils and surfaces. The soils can vary from simple dust and hair to dirt, hard water spots, and fingerprints to hardened grease, soap scum, and excrement. Although the usual household cleaning tasks are concentrated in only two rooms of the house, kitchen and bathroom, the number of different surfaces encountered are many. In the U.S., for example, there may be Formica , ceramic tiles, grout, lacquered wood, vinyl flooring, painted surfaces, brass, stainless steel, enamel, porcelain, aluminum, chrome, glass, marble, methyl methacrylate, and other types of plastics. All of these materials may occur within only two rooms of the same home ... 

An absolute width, e.g., expressed as a standard deviation in micrometers, tells very little. Figure 9.10 shows a quite wide distribution (c2 1.07) its absolute width would be about 0.7 pm, assuming it to represent a homogenized emulsion. A collection of glass marbles (dx 10 mm) tends to be very monodisperse (e.g., c2 = 0.02), but the standard deviation of the diameters would then be 200 pm, i.e., about 300 times as high. 

Camphor Water. Take i ounce nf camphor iiud cucloso it with a glass marblo in a muslin bag put this into a wide-mouthed bottle, such a one as is used for preserved fruit. Now fill up the bottle with water that has boiled a few minutes ajid has been allowed to become cold. The glass marble is used to keep tho camphor from floating, which it otherwise would do. After about 3 days tho water will become saturated with the camphor, ami may bo poured oflF as required. A wine-glassful is a dose. It is very useful os on anti-spasmodic in hysteric and nervous affections. 

Most non-scientists do not appreciate that a billion is one thousand million — and do not comprehend what a trillion — or one part per trillion means. Here is an illustration that may be of value. Imagine ordinary glass marbles about 1/2 inch in diameter — similar to the ones we played with when we were kids. An ordinary square card table will bold about 10,000 such marbles, one layer thick, packed as densely as possible. For comparison, it would take about two million marbles to cover the floor of an average size lecture hall. 

Decorative flooring and exposed aggregate systems make use of epoxies because of their low curing shrinkage, and the good bonding of glass, marble, and quartz chip by the epoxy matrix. 

Glass marble Small spheres of glass used for melting and subsequendy drawing into glass fibers. 

The idea of sintering is to join particles together without melting them. We may, however, use an additive that does melt. The particles can be crystalline or amorphous— we can sinter glass marbles as long as we do not melt them of course, the particles need not be spheres. At too high a temperature, the marbles also deform. 

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