Search

In this research study, a new solar energy-based integrated system is developed for treating industrial brine wastewater. An integrated solar-powered evaporation and membrane-based water treatment technique is utilized. Both forced convection as well as falling film evaporators are incorporated to treat high-concentration rejected brine. The system performance is assessed through a comprehensive thermodynamic investigation at varying operating parameters. The energetic performance is evaluated to vary from 12.5% to 15.9% across the year. Furthermore, the peak efficiency in terms of exergy is found to be 11.1%. Also, the membrane-based wastewater treatment subsystem is found to entail an energetic performance of 73.3% and an exergetic performance of 34.6% in terms of efficiencies. Moreover, an energetic performance of 15.4% and an exergetic performance of 2.9% is found for the evaporation-based subsystem. The exergy destructions in each system component are evaluated and the power generation subsystem is determined to have the highest exergy destruction rate of 15.4 MW. To investigate the effects of varying design parameters and operating conditions on the system performance, several parametric studies are also performed., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: In school-based smoking prevention research, it is still debatable whether parents or peers are most influential to maintained smoking among adolescents. As a result, this study examines the effects of parental and peer approval of smoking on adolescents' current levels of smoking., Methods: Poisson random-effects regression models were used to assess the effects of parental and peer approval of smoking on adolescents' (n = 913) current level of smoking., Results: Results of these analyses indicate that a stronger relationship between parental approval of smoking and current level of smoking was found for female adolescents than for male adolescents. Conversely, a stronger relationship between peer approval of smoking and current level of smoking was found for male adolescents than for female adolescents. With respect to race, the influence of parental approval of smoking on adolescents' current level of smoking was generally more pronounced for minority adolescents, relative to white adolescents. However, the influence of peer approval of smoking on current level of smoking was strongest for white adolescents and was less strong for black, Hispanic, and Asian adolescents., Conclusion: The findings of this study demonstrated that the effects of parental and peer approval of smoking on adolescents' current levels of smoking were varied by gender and race. These differential effects may have some implication for the development of future school-based smoking prevention and cessation programs., (Copyright 1999 American Health Foundation and Academic Press.)

Background: In longitudinal smoking prevention studies, a difficulty in evaluating treatment effects is understanding whether bias is associated with those who do not complete the study. This study presents the significant predictors of attrition and suggests how to reduce attrition bias in evaluating program effects., Methods: Survival analysis methods were used to assess factors associated with attrition at different time points of the study., Results: Results of the analysis indicate that those who drop out tend to be of lower academic achievement, have lower tobacco and health knowledge, and have lower social influence/resistance skills knowledge, and are more likely to be smokers and to be marijuana users. Blacks are more likely to drop out than the other ethnic groups. Gender is not a significant predictor for dropout. The dropout rates among the treatment conditions are significantly different., Conclusions: The findings of this study demonstrate that attritions in longitudinal smoking prevention studies are not at random. By considering the characteristics of dropouts, one can reduce attrition bias using available procedures and can take appropriate strategies for reducing dropout rates in future smoking prevention studies.

Background: This paper presents the student outcomes of a large-scale, social-influences-based, school and media-based tobacco use prevention and cessation project in Southern California., Methods: The study provided an experimental comparison of classroom delivery with television delivery and the combination of the two in a 2 x 2 plus 1 design. Schools were randomly assigned to conditions. Control groups included "treatment as usual" and an "attention control" with the same outcome expectancies as the treatment conditions. Students were surveyed twice in grade 7 and once in each of grades 8 and 9. The interventions occurred during grade 7., Results: We observed significant effects on mediating variables such as knowledge and prevalence estimates, and coping effort. The knowledge and prevalence estimates effects decayed partially but remained significant up to a 2-year follow-up. The coping effort effect did not persist at follow-ups. There were significant main effects of both classroom training and TV programming on knowledge and prevalence estimates and significant interactions of classroom and TV programming on knowledge (negative), disapproval of parental smoking, and coping effort. There were no consistent program effects on refusal/self-efficacy, smoking intentions, or behavior., Conclusions: Previous reports demonstrated successful development and pilot testing of program components and measures and high acceptance of the program by students and parents. The lack of behavioral effects may have been the result of imperfect program implementation or low base rates of intentions and behavior.