Assessment of the injectability of conditioned brine produced by a reaction clarification: gravity filtration system in operation at the Salton Sea geothermal field, Southern California

A Demonstration Reaction Clarifier - Gravity Filtration System with a 1600 GPM throughput capability was in operation at the joint DOE-SDG and E-MAGMA test facility located in the Salton Sea Geothermal Field, southern California, during the summer of 1979. The system, which was designed to condition spent effluent from a 10 MWe-size geothermal power plant, removes supersaturated dissolved species and residual suspended solids from brine prior to subsurface brine disposal via injection wells. The post-processing chemical stability of conditioned effluents was established by means of anaerobic incubation tests at 90/sup 0/C. The effect of residual dissolved polymer, that might be used for the purpose of scale control in upstream power plant components on the efficiency of reaction clarification, was also evaluated. Membrane filtration and core tests were used to assess the injectability of processed brine. It was found that the clarifier-filter operational procedures and system design permitted oxygenation of the brine by air intrusion. This resulted in partial stabilization of dissolved silica and precipitation of oxides of iron. As a consequence, conditioned brine injectability was poor. However, elimination of the air intrusion problem would result in a substantial improvement in brine quality. Residual amounts of dissolved polyaminoethylene (20 ppm, by weight), a powerful antisilica precipitant, in brine was shown by means of bench-scale tests carried out at approx. 90/sup 0/C to improve the efficiency of the clarification process where the additive appears to function as a flocculant

Australian Veterinary History Record No. 40

Australian Veterinary Associatio

Methane extraction from geopressured-geothermal brine at wellhead conditions

Disposal of geopressured-geothermal brine effluents by injection is expected to be costly, even into shallow aquifers. If injection into the production reservoir becomes necessary to maintain productivity and to minimize subsidence, the injection pumping costs can become overwhelming. An option aimed at reducing injection pump operating costs is to maintain a higher than normal pressure at the production wellhead to reduce the injection pumping load. The crucial element, however, is that a significant portion of CH/sub 4/ remains in solution and must be recovered in order for the pressure maintenance option to be cost effective. A laboratory and field test capability has been established, and several methods for extracting dissolved CH/sub 4/ at high temperature and pressure are being evaluated. Solvent extraction and use of hydraulic motors or turbines coupled to CH/sub 4/ recovery systems are the leading candidate methods

The efficacy of vigorous-intensity exercise as an aid to smoking cessation in adults with high anxiety sensitivity: A randomized controlled trial

Item does not contain fulltextObjectives: High anxiety sensitivity predicts poor smoking cessation outcomes. Aerobic exercise reduces anxiety sensitivity and aspects of the risk conferred by anxiety sensitivity. In the current study, we examined whether exercise can aid smoking cessation in adults with high anxiety sensitivity. Methods: Participants were sedentary and low-activity adult daily smokers (n = 136) with elevated prescreen anxiety sensitivity. Participants received 15 weeks of standard smoking cessation treatment (ST; cognitive behavioral therapy plus nicotine replacement therapy). In addition, participants were simultaneously randomized to 15 weeks of either an exercise intervention (ST + EX; n = 72) or a wellness education control condition (ST + CTRL; n = 64). Self-reported smoking abstinence was assessed weekly during the intervention, at the end of treatment (10 weeks after the target quit date), and at 4 and 6 months after the target quit date. Abstinence was verified by expired carbon monoxide readings and saliva cotinine. Results: Results indicated that point prevalence abstinence (PPA) and prolonged abstinence (PA) rates were significantly higher for ST + EX than for ST + CTRL at each of the major end points among persons with high anxiety sensitivity (PPA: b = -0.91, standard error [SE] = 0.393, t(1171) = -2.33, p = .020; PA: b = -0.98, SE = 0.346, t(132) = -2.84, p = .005), but not among those with low anxiety sensitivity (PPA: b = -0.23, SE = 0.218, t(1171) = -1.06, p = .29; PA: b = -0.31, SE = 0.306, t(132) = -1.01, p = .32). Conclusions: The present results suggest that exercise facilitates the odds of quit success for smokers with high levels of anxiety sensitivity and therefore may be a useful therapeutic tactic for this high-risk segment of the smoking population

Identifying attendance patterns in a smoking cessation treatment and their relationships with quit success

Item does not contain fulltextBackground: While important for substance use outcomes, knowledge about treatment attendance patterns, and their relation with clinical outcomes is limited. We examined the association between attendance patterns and smoking outcomes in a randomized, controlled smoking cessation intervention trial. Methods: In addition to standard smoking cessation treatment, participants were randomized to 15 weeks of an exercise intervention (n = 72) or an education control condition (n = 64). Latent class growth analysis (LCGA) tested whether intervention attendance would be better modeled as qualitatively distinct attendance patterns rather than as a single mean pattern. Multivariate generalized linear mixed modeling (GLMM) was used to evaluate associations between the attendance patterns and abstinence at the end of treatment and at 6-month follow-up. Results: The LCGA solution with three patterns characterized by high probability of attendance throughout (Completers, 46.3%), gradual decreasing probability of attendance (Titrators, 23.5%), and high probability of dropout within the first few weeks (Droppers, 30.1%) provided the best fit. The GLMM analysis indicated an interaction of attendance pattern by treatment condition, such that titration was associated with lower probability of quit success for those in the control condition. Probability of quit success was not significantly different between Titrators and Completers in the exercise condition. Conclusions: These findings underscore the importance of examining how treatment efficacy may vary as a function of attendance patterns. Importantly, treatment discontinuation is not necessarily indicative of poorer abstinence outcome