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• 1. [Image] Chloride/Magnesium Ratio of Shallow Groundwaters as a Regional Geothermal Indicator in Hawaii

  	This report discusses some of the problems in using the Si02-temperature criteria for shallow groundwater assessment and the applications of the Cl/Mg ratio. Also presented are those areas within the state ...
  	Citation × Citation Citation Abstract Copy Title: Chloride/Magnesium Ratio of Shallow Groundwaters as a Regional Geothermal Indicator in Hawaii Author: Cox, M. E. Year: 1979 This report discusses some of the problems in using the Si02-temperature criteria for shallow groundwater assessment and the applications of the Cl/Mg ratio. Also presented are those areas within the state that are considered to possess potential on the basis of their Cl/Mg ratio Title: Chloride/Magnesium Ratio of Shallow Groundwaters as a Regional Geothermal Indicator in Hawaii Author: Cox, M. E. Year: 1979 This report discusses some of the problems in using the Si02-temperature criteria for shallow groundwater assessment and the applications of the Cl/Mg ratio. Also presented are those areas within the state that are considered to possess potential on the basis of their Cl/Mg ratio Close

• 2. [Image] Study of Silica Scaling from Geothermal Brines, Final Report, November 15, 1974 - April 30, 1977

  	Condensation of silica from brines supersaturate in silicic acid was studied over a range of pH (4.5 to 6.5), temperature (75 to 105/sup 0/C), salinity, and silicic acid concentration (700 to 1200 ppM ...
  	Citation × Citation Citation Abstract Copy Title: Study of Silica Scaling from Geothermal Brines, Final Report, November 15, 1974 - April 30, 1977 Author: Makrides, A.C. Year: 1978 Condensation of silica from brines supersaturate in silicic acid was studied over a range of pH (4.5 to 6.5), temperature (75 to 105/sup 0/C), salinity, and silicic acid concentration (700 to 1200 ppM as SiO/sub 2/). The experimental technique involved analyses for molybdate-reactive silicic acid as a function of time after a supersaturated solution of Si(OH)/sub 4/ was prepared by mixing aliquots of a stock silicate solution with buffered brine. The isothermal rate of SiO/sub 2/ condensation is a strong function of supersaturation (C/Ce), pH, and salinity. The overall kinetics follow what is expected from the general theory of phase transitions. The kinetic results suggest that growth of nucleated particles is activation controlled, at least initially. The increase of condensation rate with salt content is attributed to a decrease in equilibrium solubility of SiO/sub 2/. In effect, higher salt concentrations increase supersaturation and lead to faster nucleation. Higher nucleation and growth rates are observed at higher pH's. An increase of 1 pH unit increases rates by a factor of about 10. The pH dependence is consistent with the hypothesis that SiO(OH)/sub 3//sup -/ is One of the reacting species. Temperature has little effect on condensation rate at a fixed initial silicic acid concentration. This result suggests that the increase in rate of activated steps brought about by increased temperature is essentially counterbalanced by a decrease in supersaturation (because of higher equilibrium solubility at higher temperatures). The kinetic results yield an activation energy of 17 kcal/mol for addition of silicic acid to a nucleated particle and 45 ergs/cm/sup 2/ for the interfacial energy between precipitated silica and the brine. NaCl, KCl, CaCl/sub 2/ and MgCl/sub 2/ had no specific effect on condensation rate. However, NaF had a large effect on rate; a few ppM (15 to 100) of fluoride ion accelerate condensation substantially Title: Study of Silica Scaling from Geothermal Brines, Final Report, November 15, 1974 - April 30, 1977 Author: Makrides, A.C. Year: 1978 Condensation of silica from brines supersaturate in silicic acid was studied over a range of pH (4.5 to 6.5), temperature (75 to 105/sup 0/C), salinity, and silicic acid concentration (700 to 1200 ppM as SiO/sub 2/). The experimental technique involved analyses for molybdate-reactive silicic acid as a function of time after a supersaturated solution of Si(OH)/sub 4/ was prepared by mixing aliquots of a stock silicate solution with buffered brine. The isothermal rate of SiO/sub 2/ condensation is a strong function of supersaturation (C/Ce), pH, and salinity. The overall kinetics follow what is expected from the general theory of phase transitions. The kinetic results suggest that growth of nucleated particles is activation controlled, at least initially. The increase of condensation rate with salt content is attributed to a decrease in equilibrium solubility of SiO/sub 2/. In effect, higher salt concentrations increase supersaturation and lead to faster nucleation. Higher nucleation and growth rates are observed at higher pH's. An increase of 1 pH unit increases rates by a factor of about 10. The pH dependence is consistent with the hypothesis that SiO(OH)/sub 3//sup -/ is One of the reacting species. Temperature has little effect on condensation rate at a fixed initial silicic acid concentration. This result suggests that the increase in rate of activated steps brought about by increased temperature is essentially counterbalanced by a decrease in supersaturation (because of higher equilibrium solubility at higher temperatures). The kinetic results yield an activation energy of 17 kcal/mol for addition of silicic acid to a nucleated particle and 45 ergs/cm/sup 2/ for the interfacial energy between precipitated silica and the brine. NaCl, KCl, CaCl/sub 2/ and MgCl/sub 2/ had no specific effect on condensation rate. However, NaF had a large effect on rate; a few ppM (15 to 100) of fluoride ion accelerate condensation substantially Close

• 3. [Image] Viscosity of Brines from the Salton Sea Geothermal Field, Imperial Valley, California

  	The viscosity of chemically analyzed brines from the Salton Sea Geothermal Field was measured from 5 to 90/sup 0/C at 100 kPa. Data indicate that these multicomponent solutions are slightly more viscous ...
  	Citation × Citation Citation Abstract Copy Title: Viscosity of Brines from the Salton Sea Geothermal Field, Imperial Valley, California Author: Piwinskii, A.J. Year: 1977 The viscosity of chemically analyzed brines from the Salton Sea Geothermal Field was measured from 5 to 90/sup 0/C at 100 kPa. Data indicate that these multicomponent solutions are slightly more viscous than a 3.5 molal NaCl solution in this temperature interval Title: Viscosity of Brines from the Salton Sea Geothermal Field, Imperial Valley, California Author: Piwinskii, A.J. Year: 1977 The viscosity of chemically analyzed brines from the Salton Sea Geothermal Field was measured from 5 to 90/sup 0/C at 100 kPa. Data indicate that these multicomponent solutions are slightly more viscous than a 3.5 molal NaCl solution in this temperature interval Close

• 4. [Article] Transport of chloride ions during accelerated cathodic protection of reinforced concrete structures

  Chloride ion migration was studied under accelerated cathodic protection conditions using 6" x 6" x 6" mortar blocks of varying initial chloride content and water to cement ratios. An iron mesh embedded ...

  Citation × Citation Citation Abstract Copy Title: Transport of chloride ions during accelerated cathodic protection of reinforced concrete structures Author: Rehani, Manu Chloride ion migration was studied under accelerated cathodic protection conditions using 6" x 6" x 6" mortar blocks of varying initial chloride content and water to cement ratios. An iron mesh embedded parallel to one face in the blocks acted as the cathode and zinc was thermally sprayed on the opposite face to form an anode. First, the potential response of two blocks was studied at a current density of 3 mA/ft². One block was outfitted with a heat sink and moisture barrier while the other block was periodically wetted. Second, eight blocks were polarized at various current densities for a period of one year. In both sets of experiments, the blocks were maintained in controlled humidity and temperature. The potential across the blocks was recorded at periodic intervals and mortar samples were drilled to measure the chloride content as a function of aging. Based on observations of the first study a theoretical model was constructed which indicates that zinc based electrochemical products form at the zinc-concrete interface. The effect of the electrochemical product on raising the resistance across a cathodic protection set-up may be of consequence and should be further studied. Blocks polarized at 6 mA/ft² exhibited similar behavior as the blocks polarized at 3 mA/ft², but the response was twice as fast. This result indicates that studying cathodic protection under accelerated conditions is valid. The chloride content of samples obtained from one set of blocks over the course of the experiment was normalized against the initial chloride profile. The normalized profiles were calculated as a function of aging and they supported the hypothesis that chloride ions would move away from the rebar and towards the sprayed zinc anode under cathodic protection. Title: Transport of chloride ions during accelerated cathodic protection of reinforced concrete structures Author: Rehani, Manu Chloride ion migration was studied under accelerated cathodic protection conditions using 6" x 6" x 6" mortar blocks of varying initial chloride content and water to cement ratios. An iron mesh embedded parallel to one face in the blocks acted as the cathode and zinc was thermally sprayed on the opposite face to form an anode. First, the potential response of two blocks was studied at a current density of 3 mA/ft². One block was outfitted with a heat sink and moisture barrier while the other block was periodically wetted. Second, eight blocks were polarized at various current densities for a period of one year. In both sets of experiments, the blocks were maintained in controlled humidity and temperature. The potential across the blocks was recorded at periodic intervals and mortar samples were drilled to measure the chloride content as a function of aging. Based on observations of the first study a theoretical model was constructed which indicates that zinc based electrochemical products form at the zinc-concrete interface. The effect of the electrochemical product on raising the resistance across a cathodic protection set-up may be of consequence and should be further studied. Blocks polarized at 6 mA/ft² exhibited similar behavior as the blocks polarized at 3 mA/ft², but the response was twice as fast. This result indicates that studying cathodic protection under accelerated conditions is valid. The chloride content of samples obtained from one set of blocks over the course of the experiment was normalized against the initial chloride profile. The normalized profiles were calculated as a function of aging and they supported the hypothesis that chloride ions would move away from the rebar and towards the sprayed zinc anode under cathodic protection. Close