Bomb carbon

Because water in the deep ocean mixes on time scales of 500-1000 y, the C content of DIG in the vast majority of the deep sea waters is still largely unaffected by bomb carbon. In fact, it is via the determination of the C age of deep sea DIG that we know the approximate circulation time of the deep ocean. This is illustrated... 

War elements are associated in various ways with war e.g., antimony (a component of Greek fire), arsenic (a component in mustard gas), beryllium (evolved through nuclear bombs), carbon, (in gun powder), chlorine (the main ingredient of poison gas), iron (swords), manganese (in armour), nitrogen (in explosives), phosphorus (in bombs an nerve gases), plutonium (from classical the atomic bomb), sulfur (in gunpowder), uranium (in atomic bombs), and vanadium (in armour) [48]. 

The use of larger particles in the cyclotron, for example carbon, nitrogen or oxygen ions, enabled elements of several units of atomic number beyond uranium to be synthesised. Einsteinium and fermium were obtained by this method and separated by ion-exchange. and indeed first identified by the appearance of their concentration peaks on the elution graph at the places expected for atomic numbers 99 and 100. The concentrations available when this was done were measured not in gcm but in atoms cm. The same elements became available in greater quantity when the first hydrogen bomb was exploded, when they were found in the fission products. Element 101, mendelevium, was made by a-particle bombardment of einsteinium, and nobelium (102) by fusion of curium and the carbon-13 isotope. 

Organic selenium compounds and siUceous materials (rock, ore, concentrates) are fused with mixtures of sodium carbonate and various oxidants, eg, sodium peroxide, potassium nitrate, or potassium persulfate. For volatile compounds, this fusion is performed in a bomb or a closed system microwave digestion vessel. An oxidizing fusion usually converts selenium into Se(VI) rather than Se(IV). 

Kea.tlte, Keatite has been prepared (65) by the crystallisation of amorphous precipitated silica ia a hydrothermal bomb from dilute alkah hydroxide or carbonate solutions at 380—585°C and 35—120 MPa (345—1180 atm). The stmcture (66) is tetragonal. There are 12 Si02 units ia the unit cell ttg = 745 pm and Cg = 8604 pm the space group is P42. Keatite has a negative volumetric expansion coefficient from 20—550°C. It is unchanged by beating at 1100°C, but is transformed completely to cristobahte ia three hours at 1620°C. 

Tungsten oxydichlofide [13520-76-8], WO2CI2, a pale-yeUow crystalline soHd having an mp of 266°C, is soluble in cold water and in alkaline solution, although partly decomposed by hot water. It is prepared by the action of carbon tetrachloride on tungsten dioxide at 250°C in a bomb (13). 

A unique problem arises when reducing the fissile isotope The amount of that can be reduced is limited by its critical mass. In these cases, where the charge must be kept relatively small, calcium becomes the preferred reductant, and iodine is often used as a reaction booster. This method was introduced by Baker in 1946 (54). Researchers at Los Alamos National Laboratory have recently introduced a laser-initiated modification to this reduction process that offers several advantages (55). A carbon dioxide laser is used to initiate the reaction between UF and calcium metal. This new method does not requite induction heating in a closed bomb, nor does it utilize iodine as a booster. This promising technology has been demonstrated on a 200 g scale. 

In the calcium refining process, the chromium reacts with calcium vapor at about 1000°C ia a titanium-lined bomb, which is first evacuated and then heated to the proper temperature. A pressure of about 2.7 Pa (20 p.m Hg) is maintained during heating until the calcium vapor reaches the cold end of the bomb and condenses. This allows the calcium vapor to pass up through the chromium metal where it reacts with the oxygen. Metal obtained by this process contains 0.027 wt % oxygen, 0.0018 wt % nitrogen, 0.008 wt % carbon, 0.012 wt % sulfur, and 0.015 wt % iron. 

When acetone was not used for washing out the bomb, a fraction weighing 70-75 g. was obtained by the submitters. After drying over anhydrous potassium carbonate, they obtained, by fractional distillation, 3-6 g. of a-methyltetrah3 dro-furan, b.p. SO-81 , and 23-28 g. of K-amyl alcohol, b.p. 137-138°. The alcohol obtained was pure, and neither secondary amyl nor butyl alcohols could be detected. 

The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113°C to 22.799°C. The calorimeter assembly is known to have a total heat capacity of 3.00 kJ-(°C). (a) Write a balanced equation for the reaction. 

Most CO and CO2 in the atmosphere contain the mass 12 isotope of carbon. However, due to the reaction of cosmic ray neutrons with nitrogen in the upper atmosphere, C is produced. Nuclear bomb explosions also produce C. The C is oxidized, first to CO and then to C02 by OH- radicals. As a result, all CO2 in the atmosphere contains some 0, currently a fraction of ca. 10 of all CO2. Since C is radioactive (j -emitter, 0.156 MeV, half-life of 5770 years), all atmospheric CO2 is slightly radioactive. Again, since atmospheric CO2 is the carbon source for photos5mthesis, aU biomass contains C and its level of radioactivity can be used to date the age of the biological material. 

The gross flux of carbon from atmosphere to ocean is thus ca. 80 Pg C/yr. There are several complications with the above calculation. The isotopic ratios must be steady-state values, which are unavailable due to the changes resulting from atmospheric atom bomb testing. The few available pre-bomb measurements from the late 1950s (Broecker et ah, 1960) together with determinations in corals (Druffel and Linick, 1978) are invaluable tools for determin-... 

Fig. 11-24 Carbon-14 in the troposphere and the ocean surface water 1962-1981. values for ocean surface water during this period range from 0-15% with no trend over time. (Modified with permission from R. Nydal and K. Lovseth (1983). Tracing bomb in the atmosphere. /. Geophys. Res. 88, 3621-3642, American Geophysical Union.)...

A PET oligomer isolation method has utilised chloroform extraction in a Parr bomb lined with a Teflon-TFE fluoro-carbon resin [40]. The analytics of fluoropolymer processing aids (combustion analysis, XRF, EUR, 19F NMR, OM) have recently been described [29]. Combustion analysis (Parr Oxygen Bomb Calorimeter) can be used for quantitative analysis... 

A mass of evidence seems to confirm that the mixing rate of radiocarbon in the atmosphere is rapid, and that with respect to its radiocarbon content the atmosphere can be considered as a homogeneous entirety. The contamination of samples with matter from an extraneous source can nevertheless invalidate this assumption. Two types of contamination can be differentiated physicochemical contamination and mechanical intrusion. There are two forms of physicochemical contamination. One is due to the dilution of the concentration of radiocarbon in the atmosphere by very old carbon, practically depleted of radiocarbon, released by the combustion of fossil fuel, such as coal and oil. The other is by the contamination with radiocarbon produced by nuclear bomb tests during the 1950s and later in the twentieth century. The uncertainties introduced by these forms of contamination complicate the interpretation of data obtained by the radiocarbon dating method and restrict its accuracy and the effective time range of dating. 

Dining interaction at ambient temperature in a bomb to produce poly (carbon monofluoride), admission of fluorine beyond a pressure of 13.6 bar must be extremely slow and carefully controlled to avoid a violently exothermic explosion [1], Previously it had been shown that explosive interaction of carbon and fluorine was due to the formation and decomposition of the graphite intercalation compound, poly (carbon monofluoride) [2], Presence of mercury compounds prevents explosion during interaction of charcoal and fluorine [3], Reaction of surplus fluorine with graphite or carbon pellets was formerly used as a disposal method, but is no longer recommended. Violent reactions observed when an exhausted trap was opened usually involved external impact on the metal trap, prodding the trap contents to empty the trap, or possibly ingress of moist air... 

The SOM 14C apparent age of soil section (0-0.05 m) is 80 yr B.R for WKS profile and 140 yr B.R for QYS profile, suggesting that the upper soil layers had been contaminated by some old carbons with negative A14C values. Contaminations from old carbon and bomb 14C can result in obvious alterations in SOM A14C values. However, SOM 513C value is relatively less susceptible to such contaminations, because the abundance of 13C is much greater than that of 14C in nature system. This indicates that 14C analysis alone is not adequate for studying SOM dynamics. 

Table I. Hydrogenation of carbon monoxide with ruthenium catalysts. All reactions performed in a glass-lined rocker bomb with 2.35 mmol Ru (charged as RU3CO) 2), at 230°C under 340 atm 1 1 H2/CO for 2 h, unless noted otherwise.

Broecker and Li (1970) and Broecker (1974) found that the 14C/12C ratio in the deep ocean was 84 percent of this ratio in the pre-bomb surface ocean. Assuming that surface carbon (dissolved and falling debris) is the only source of deep ocean carbon, calculate the residence time tc of this element in the deep-ocean. The 14C decay constant is 1.2 x 10 4a 1. 

In equations 7.27 and 7.28 m(BA), m(cot), m(crbl), and m(wr) are the masses of benzoic acid sample, cotton thread fuse, platinum crucible, and platinum fuse wire initially placed inside the bomb, respectively n(02) is the amount of substance of oxygen inside the bomb n(C02) is the amount of substance of carbon dioxide formed in the reaction Am(H20) is the difference between the mass of water initially present inside the calorimeter proper and that of the standard initial calorimetric system and cy (BA), cy(Pt),cy (cot), Cy(02), and Cy(C02)are the heat capacities at constant volume of benzoic acid, platinum, cotton, oxygen, and carbon dioxide, respectively. The terms e (H20) and f(sin) represent the effective heat capacities of the two-phase systems present inside the bomb in the initial state (liquid water+water vapor) and in the final state (final bomb solution + water vapor), respectively. In the case of the combustion of compounds containing the elements C, H, O, and N, at 298.15 K, these terms are given by [44]... 

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