Electrolyte drainage

Absorptive glass mat (AGM) Very high porosity of separator High purity and stability of separator Low internal electrical resistance Relatively large separator pores acid stratification -electrolyte drainage risk of internal shorts -risk of thermal runaway -risk of PCL-3... 

Little electrolyte drainage Relatively high internal resistance... 

Cable sheaths may be covered with paper and hessian wrappings impregnated with bituminous compounds or with extruded or taped plastics outer sheaths. At pinholes or discontinuities in protective coatings the sheath will be particularly liable to electrolytic corrosion in stray-current areas, and it is desirable to supplement this form of protection by drainage bonds or direct cathodic protection. 

Drainage (electric drainage) (a) flow of positive current through the soil or the electrolyte solution from the cathodically protected structure to the groundbed of the impressed current system, or (b) protection of an immersed structure from electrochemical corrosion by making an electrical connection between the structure and the negative return circuit (rail, feeder, busbar) of a d.c. electric traction system. 

Environment Removal of water or electrolytes that increase conductivity Design to facilitate drainage of water drainage of soils... 

The function of the electrolyte membrane is to facilitate transport of protons from anode to cathode and to serve as an effective barrier to reactant crossover. The electrodes host the electrochemical reactions within the catalyst layer and provide electronic conductivity, and pathways for reactant supply to the catalyst and removal of products from the catalyst [96], The GDL is a carbon paper of 0.2 0.5 mm thickness that provides rigidity and support to the membrane electrode assembly (MEA). It incorporates hydrophobic material that facilitates the product water drainage and prevents... 

Polyserositis (manifesting as pleural effusions or ascitis) are common, but drainage procedures should be avoided unless the effusions worsen patient s ventilation, as they may lead to severe internal haemorrhage. Hypoglycaemia, metabolic acidosis, electrolyte disturbances should be looked for... 

This finding is supported by the results obtained at constant NaDoS concentration and various NaCl concentrations. All points, depicted for NaCl concentration up to 0.32 mol dm 3 lay on curve 1, while for concentrations higher than that, lay on curve 2. Thus, a critical electrolyte concentration Cei,cr is determined which is decisive for the formation of the respective type of foam films. Its value, Cei,cr = 0.33 0.05 mol dm 3, is in a better agreement with the values obtained employing other techniques for foams (see Chapter 6) and foam films (Chapter 3). This result evidences that the foam film type affects the drainage process. However, a quantitative interpretation is not possible. This refers to the jump in the value of the drainage rate (initial slopes) in W(t) dependence for the different types of foam films but does not answer the question why the liquid from a CBF foam drains faster. The solution of these and other problems related to the type of foam films requires its correlating with the... 

These studies were performed at high surfactant concentrations (> 0.01 mol dm 3) where the appearance of -potential was hard to explain. Unclear remained the fact that f-potential did not depend on the electrolyte concentration (NaCl) up to a value of 3%. Anomalously high values of -potential ( 0.5 V) have been reported by Laniquielli and Galembeck [64] who studied electrokinetic phenomena occurring at gravitational foam drainage. They attribute this anomaly to the electrolyte accumulation in the electrode space. The analysis of these results indicates that reliable values of the -potential in foams can be derived with an especially developed theory of the electrokinetic phenomena in foams that accounts for the peculiarities of these systems. Furthermore, new apparatus is needed to allow the study of foams with controlled border sizes and precisely defined border profile. 

Drainage water from coal mines is frequently charged with ferrous sulphate consequent upon the oxidation of pyrites in the coal, and upon evaporation yields the impure salt. The salt is readily obtained in a pure state by dissolving electrolytic iron in dilute sulphuric acid and allowing to crystallise, preferably in an inert atmosphere. Commercially ferrous sulphate is obtained by exposing heaps of pyrites to the oxidising action of the air. Ferrous sulphate and free sulphuric acid drain off into tanks, the acid being neutralised with scrap iron —... 

Continuous Phase Composition Emulsion liquid membrane properties can be significantly influenced by changing the composition of the external aqueous phase. Emulsion stability can be improved by an increase in the viscosity as a result of the decrease in the rate of fluid drainage between the liquid films [88]. An increase in ionic strength of the external phase has been shown to cause a decrease in entrainment phenomena during permeation. This has been attributed to an alteration of the stmcture of the interface between the emulsion and the external phase promoted by the presence of electrolytes in the external phase. A reduction in osmosis also occurs due to a reduction in the chemical potential difference between both sides of the membrane [94,98]. 

Urine collection for Na, or Cl assay should be made without the addition of preservatives. Feces and aspirates and drainages from different portions of the gastrointestinal tract may also be submitted for electrolyte analysis. Collection and analysis of sweat are described later in this chapter. 

There are also problems dealing with fluoride-contaminated discharge water from wet scrubbers, and the drainage of precipitation from areas where spent pot linings are discarded, since fluoride constituents of electrolyte leach from these. Careful disposal of spent pot linings can minimize this problem. The problem may be eliminated by fluoride recovery followed by recycle of the carbon content. 

Discarded pot linings still contain 10-15% absorbed fluorides, which could cause an environmental hazard. However, increased costs for electrolyte fluoride replacement have stimulated more smelters to crush used pot linings and recover the fluoride content by extraction with aqueous base. The filtered extract is then used for the preparation of synthetic cryolite. If spent pot linings are discarded to a landfill, any drainage from the site has to be treated. Landfill disposal also has a risk of occasional fires from spontaneous ignition of lining material. 

Acid drainage is an extreme case of gravity effects in VRLA cells. In very tall cells or in cells built with low surface-area or glass/organic hybrid separators combined with low compression levels electrolyte can actually pool in the bottom of the cell, even at moderate or high saturation levels. This creates a condition where the bottom of the cell charges as if it were a flooded lead-acid cell (which it is) and the upper portions of the cell try to function as a normal. 

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