Oxygen cell

Zinc oxide beds Zinc oxide eugenol Zinc oxides Zinc-oxygen cell... 

Zinc—Oxygen Cells. On the basis of reactants the zinc—oxygen or air system is the highest energy density system of all the alkaline rechargeable systems with the exception of the 2 Th reactants are cheap and abundant and therefore a number of attempts have been made to develop a practical rechargeable system. The reactions of this system are as follows ... 

Hydrogen—Oxygen Cells. The hydrogen—oxygen cell can be adapted to function as a rechargeable battery, although this system is best known as a primary one (see Fuel cells). The electrochemical reactions iavolve ... 

The hydrogen-oxygen cell used in the space shuttle is called an alkali fuel cell, because it has an alkaline electrolyte ... 

Zinc oxide-eugenol surgical pastes, 8 286 Zinc oxide treatments, 26 613-614 Zinc-oxygen cells, 3 512-515 Zinc perchlorate, 18 278 Zinc peroxide, 18 397 Zinc phenolsulfonate... 

The electromotive force of an electrochemical cell is the difference in electrode potential between the two electrodes in the cell. According to the TUPAC convention, the electromotive force is the potential of the right hand electrode referred to the potential of the left hand electrode. We consider, for example, a hydrogen-oxygen cell shown in Fig. 6—4 the cell reaction is given by Eqn. 6-1 and the cell diagram is given by Eqn. 6-5 ... 

Figure 4-3 Reversible Voltage of The Hydrogen-Oxygen Cell (14)... 

Cisplatin was first characterized as a radiation sensitizer using hypoxic Bacillus megaterium spores (53). Radiation sensitization by cisplatin was confirmed in vegetative Escherichia coli with a maximum sensitizer enhancement ratio of 1.77 in anoxic bacteria at a cisplatin concentration of 50 uM (54). Zimbrick et al. (55) extended these studies to other platinum complexes. The earliest studies in mammalian cells used hypoxic V-79 Chinese hamster cells and showed a small radiation sensitization with 8 iM of cisplatin (56). Nias and Szumiel (57) first reported that pretreatment of Chinese hamster ovary (CHO) cells with a platinum complex could sensitize well-oxygenated cells to radiation. Wodinsky etal. (58) showed that cisplatin potentiated the effect of whole-body radiation therapy in mice inoculated intraperitoneally with P388 leukemia compared with either modality alone. Therapeutic potentiation was found in MTG-B subcutaneous tumors and intracerebral RBT when the animals were treated with cisplatin and radiation (59). 

In an excellent review of the literature on the interaction between radiation and the taxanes, especially looking at the effects of paclitaxel, Milas et al.(38) outline how they came to realize that reoxygenation played such a substantial role in the potentiation of tumor radioresponse. It has been well established for years that tumors contain areas of hypoxic cells that are normally 2.5 to 3 times less sensitive to radiation than normal cells (37). Both radiation and chemotherapies can cause reoxygenation through their preferential killing of those oxygenated cells that are located close to blood vessels. Milas et al. summarized observations that showed ... 

Hypoxic cells are three times more radio-resistant than well-oxygenated cells (OER = 3) for low-LET radiation. The presence of a small percentage of hypoxic cells (1% or even 0.1%) can thus make the tumor radio-resistant. 

The electrodes in the hydrogen-oxygen cell are porous carbon rods that contain a platinum catalyst. The electrolyte is a hot (several hundred degrees) potassium hydroxide solution. Hydrogen is oxidized at the anode where the hydrogen and hydroxide ions combine to form water. Electrons flow through the external circuit. 

Table 9.1 Emf and theoretical energy density of practical metal-oxygen cells...

OXYGEN CELL. An electrolytic cell whose emf is due to a difference in oxygen concentration at one electrode compared with that at another electrode of the same material. 

Sensitization of anoxic cells is also brought about by non-toxic concentrations of transition metal ions (< some 10-4 mol dm-3) such as Cu(I). A dose-modifying factor of 1.5 (at 6.6 x 10-5 mol dm-3 Cu(I)) has been observed for mammalian cells (Hesslewood et al. 1978), but no sensitizing effects were observed for oxygenated cells. Under anoxic conditions, reduction of Cu(II) to Cu(I) occurs within the cells without an added reductant (see also Cramp 1967). It would be premature to come up with detailled mechanistic concepts, but some aspects of the actions of transition-metal ions have been discussed in Chapter 2.5. 

We will consider these cells, primarily the oxygen cells, under open circuit conditions and under load (or even short-circuit condition). In the transient and in the steady state it is not necessary to treat them all in detail, since (as outlined below) cells with one selectively blocking electrode and those with two of the same kind show far-reaching similarities (compare cell 3 with cell 4 and cell 5 with cell 6). The same is true if we compare cells with electrodes that are selectively blocking for electrons with cells that are specifically blocking for ions (compare cell 3 with cell 5 and cell 4 with cell 6) it is easy to show that the relations are symmetrical as regards the indices e" and O2" (see below and Appendix l).21011... 

A fuel cell is an electrochemical cell in which the reagents of the cell reaction are continuously supplied and the products are continuously removed. The most commonly used fuel cell is the hydrogen-oxygen cell with a NaOH electrolyte and graphite electrodes ... 

The temperature dependence of the reaction affinity is given by Eq. 4.8, and the result for the hydrogen-oxygen cell is shown in Eq. 9.28 ... 

Fig. 13.46. Zinc-oxygen cell voltages and available capacity for different rates of discharge measured for two 25-cm2 cells with pasted zinc electrodes containing 10 wt.% cellulose fibers with a fiber length of 1 mm. Discharge currents are x, 0.064 A o, 0.3 A a, 0.6 A a, 0.9 A , 1.2 A. (Reprinted from K. Muller, R. Holze, and O. Haas, Progress Towards a 20 Ah/12V Electrically Rechargeable Zinc/Air Battery in Batteries for Portable Applications and Electric Vehicles, C. F. Holmes and A. R. Landgrebe, eds., Electrochemical Society Proc. PV 97-18, pp. 859-868, Fig. 3,1997. Reproduced by permission of The Electrochemical Society, Inc.)...

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