Earth, siliceous

To 17 C of a culture obtained by submerged fermentation as mentioned above, siliceous earth is added and the batch is filtered. The mixture of mycelium and the siliceous earth are agi-tatedforl hour with 2.5 Cof butanol. This treatment is repeated twice. Thebutanolic extracts are combined, washed with water, evaporated to dry ness (about 10 g) and boiled with acetone (80 ml). The residue (5.41 g of yellowish powder) is distamycin. 

Melamina. Ital dynamite invented in 1873 consisting of NG absorbed in a mixt of powd charcoal and siliceous earth Ref Davis (1943), 198... 

Paulille s White Dynamite. Consisted of 70-75% NG absorbed on 30-25% natural siliceous earth Ref Daniel (1902), 73... 

Convergent margins are generally considered to be the principle present-day tectonic setting where new continental crust is formed (-1.1 kmVyr, Reymer and Schubert 1984). As illustrated on Figure 23, this new crustal material is characterized by Th/U ratios that are even lower than the Th/U ratio of the MORB mantle (2.6, Sun and McDonough 1989) yet the Th/U ratio of the bulk continental crust (3.9, Rudnick and Fountain 1995) is close to the Th/U ratio of the bulk silicate earth (see Bourdon and Sims 2003). There are several possible explanations for this paradox. Firstly, it is possible that the processes that formed the continental crust in the past were different to those in operation today. Since... 

Neuberg Siliceous Earth Natural mixture of quartz and kaolinite 2.6... 

For identification, the same two tests as for aspirin itself were prescribed then (U.S.P. XII) and now (U.S.P. XIX) however, due to the pioneering work of Higuchi, Banes, Smith and Levine in the SO s,80 a test for non-aspirin salicylates was introduced using a siliceous earth column for separation from excipients and aspirin, and spectrophotometric finish at 306 nm. A limit of 0.3% is specified. 

As mentioned in the historical synopsis (Section 5.1), Levine121 perfected the compendial partition column procedure in which aspirin in chloroform is first trapped in an immobile phase of sodium bicarbonate on a column of siliceous earth (celite) then eluted with a solution of acetic acid in chloroform and measured spectrophotometrically. This has been also used for separation in combination products.80 For the determination of salicylic acid in presence of aspirin by this method, see Section 5.61. Ion exchange columns filled with strongly or weakly basic anion exchange resin in the acetate or chloride cycle have also been used for separation of aspirin in combination products. 122 123/l2lf This has also been adapted for a student experiment.125 A Sepha-dex-G25 column has been used for the separation of aspirin from salicylic acid.126... 

The temperature of 50% condensation of a given element in the Solar Nebula defined by Wasson (1985) is 1037 K for Cu and 660 K for Zn. The much more volatile character of Zn with respect to Cu conditions the relative abundances of the two elements among the dififerent classes of chondrites. Copper concentrations vary from 80 to 120 ppm in carbonaceous and ordinary chondrites (Newsom 1995). In contrast, Zn concentrations decrease from 310 ppm in the volatile-rich Cl to 100 ppm in CO and CV, and to 50 ppm in ordinary chondrites. McDonough and Sun (1995) estimate the Cu and Zn content of the Bulk Silicate Earth to be 30 and 55 ppm, respectively. 

Zheng Y. F. (1993b). Calculation of oxygen isotope fractionation in hydroxyl-bearing silicates. Earth Planet. Set Letters, 120 247-263. 

Lithium isotope geochemistry is characterized by a difference close to 30%c between ocean water (5 Li + 31%c) and bulk silicate earth with a 8 Li-value of 3.2%c (Seitz et al. 2007). In this respect lithium isotope geochemistry is very similar to that of boron (see p. 45). The isotopic difference between the mantle and the ocean can be used as a powerful tracer to constrain water/ rock interactions (Tomaszak 2004). Figure 2.6 gives an overview of Li-isotope variations in major geological reservoirs. 

One of the most important qnestions in the genesis of ore deposits is the origin of the metals. Recent analytical developments have provided a new tool for the analysis of metal isotopes (Fe, Cu, Zn, Mo). Since the bulk silicate earth (crust+mantle) shows a uniform mean isotope composition of the metals, different metal reservoirs with distinct isotopic compositions are not easily recognizable. Thus, investigations by Markl et al. (2006a, b) on Cu and Fe ores have indicated that tracing of ore sources is ambiguous. 

The Pb-Pb isochron was made famous by the determination of the age of the Earth Patterson (1956) grouped meteorite samples with a sediment sample that is supposed to represent the bulk silicate Earth in terms of Pb isotopes (Figure 5-8). The assumption is that the Earth formed at roughly the same time as the meteorites. The colinearity of the data in Figure 5-8 is viewed as verification of the assumption. The age given by Patterson (1956) is 4.55 Ga. 

Figure 5-8 A Pb-Pb isochron that determined the age of the Earth to be about 4.55 Ga. Stony and iron meteorites as well as a sediment of the Earth are plotted on a Pb-Pb isochron. The sediment, as a "bulk sample of the silicate Earth in terms of Pb isotopes, plots on the same line as the meteorites, suggesting that the Earth and meteorites formed at the same time and are the same age. Erom Patterson (1956). Later studies reveal a more detailed evolution history of the Earth, including core formation (about 4.53 Ga), atmospheric formation (about 4.45 Ga), and crustal evolution.

The United States Pharmacopoeia 23 [11] and Indonesian Pharmacopoeia IV [9] describe the assay of benzoic acid and salicylic acid in ointments. Two chromatographic columns (20 x 2.5 cm) are used to effect the separation. One transfers a mixture of 1 g siliceous earth and 0.5 mL diluted phosphoric acid (3 in 10) to the first column (A), then packs above this a mixture of 4 g siliceous earth and ferric chloride-urea reagent. A mixture of 4 g siliceous earth and 2mL of sodium bicarbonate solution (1 in 12) is packed into the second column (B). For analysis, column A is mounted directly above column B. The sample solution is inserted onto column A, allowed to pass into the column, and then washed with 2-40 mL of chloroform. Benzoic acid can be eluted from column B by using a 3 in 100 solution of glacial acetic acid in chloroform. The benzoic acid content then can be determined by a spectrophotometric method such as that described earlier (section 4.5). 

Wang and Li have reported the determination of procaine hydrochloride injections, and the quality control of 4-aminobenzoic acid [144]. The column packing used for this work consisted of 8 g of silanized siliceous earth support with 5 mL of hexanol as the stationary phase, previously percolated with 20 mL of 0.05 M sodium carbonate. The drug injection solution (containing 10 mg of procaine hydrochloride) was applied to the column, and eluted with 30 mL of 0.05 M sodium carbonate. The eluent was diluted to 50 mL with water, and 4-aminobenzoic acid was determined by an absorbance measurement at 266 nm. Procaine was then eluted from the column using 60 mL of 0.1 M hydrochloric acid. This eluent was treated with 10 mL of acetate buffer (pH 6), and diluted to 100 ml with water. The analyte was determined on the basis of its absorbance at 290 nm. Equations for the computation of procaine and 4-aminobenzoic acid concentrations were presented. 

In the following year Hatchett was made a Fellow of the Royal Society. In 1798 he analyzed an earthy substance, sydneia, which Josiah Wedgwood had found in New South Wales and another specimen of it provided by Sir Joseph Banks (5). This, according to Wedgwood, was composed of a fine white sand, a soft white earth, some colourless micaceous particles, and some which were black. Hatchett found it to consist of siliceous earth, alumine, oxide of iron, and black lead or graphite and concluded that the Sydneian genus, in future, must be omitted in the mineral system. ... 

Scheele stated that the acid of fluorspar [hydrofluoric acid] can dissolve siliceous earth and that therefore it is almost impossible to prepare the pure acid. He believed that the earthy deposit in the receiver (Marggraf s volatile earth ) was siliceous earth produced by a reaction... 

Osmium isotopic ratio of the bulk silicate Earth overlaps measurements of ordinary chondrites but is distinct from other chondrite groups. Adapted from Righter et al. (2006). 

Hackel has extended Hibbert s observations concerning the influence of certain substances on the formation of nitroglycerine crystals of different forms. Thus, adding urethane, phenylurethane, collodion, nitrocotton, cyclonite, tetryl, dinitrobenzene, or centralites I and II promotes the formation of the labile form. Admixtures of siliceous earth, trinitrobenzene, TNT, favour the creation of the stable form. 

Nitroglycerine that escapes onto the floor or onto parts of the machinery, etc. should be removed by means of a sponge from which it is then extracted and rinsed under a stream of water into a special vessel for nitroglycerine waste. The spillage area should then be washed with water, by means of another sponge. If acid escapes the area should be covered with siliceous earth or with fine sand, and the whole removed by means of a shovel and drowned in a large amount of water. A copper or aluminium shovel is necessary in case nitroglycerine is present in the acid. 

Blanche Dynamite de Paulilles. An old expl similar to Dynamite No 1 and contg NG 70-75 siliceous earth 30-25%... 

The W isotopic compositions of various terrestrial samples, chondrites, iron meteorites, basaltic achondrites, lunar samples, and Martian meteorites are expressed as deviations in parts per 104 from the value for the silicate earth (such as the W in a drill bit or chisel), which are the same as those of average solar system materials, represented by carbonaceous chondrites. These values are summarized in Fig. 8.9, from which it can be seen that early segregated metals such as the iron meteorites and metals from ordinary chondrites have only unradiogenic W because they formed early with low Hf/W. The time differences between metal objects segregated from parents with chondritic Hf/W are revealed by the differences in W isotopic compositions between each of the metal objects and chondrites. The Hf-W model ages of all these metals indicate that all of their parent bodies formed within a few million years, implying rapid accretion in the early history of the solar system. 

Chromatographic System (See Chromatography, Appendix IIA.) Use a gas chromatograph equipped with a flame-ionization detector and containing a 2.4-m x 4-mm borosilicate glass column, or equivalent, packed with 2% liquid phase 5% phenyl methyl silicone (SE 52, or equivalent) on an 80- to 100-mesh siliceous earth support (Diatoport S, or equivalent). Maintain the column isothermally at a temperature between 270° and 280°, and the injection port and detector block at about 310°. Use helium as the carrier gas at a flow rate of about 70 mL/min. 

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