Salt recovery from agricultural drainage water using a liquid film solar-assisted concentrator – Simulation and model validation

Salt management in irrigated agriculture is critical to the economies of the San Joaquin Valley of California and many other areas around the world. Purified salts can be recovered as marketable products through fractional crystallization following concentration of final stage drainage water from integrated on-farm drainage management systems. To obtain recovered salt and use as a commercial product, new systems which can perform with higher efficiency and lower environmental impact than solar evaporation basins or solar ponds that have previously been used for the final stage are in need of development. For this purpose, a number of solar-assisted brine concentration concepts have been explored, including an open liquid film-type using a tilted evaporation surface described here. Model performance was conceptually evaluated and then experimentally verified.A transient model was developed from energy and component mass balances and employed constitutive heat and mass transfer relationships from various other sources for simulating concentration of agricultural drainage water using a liquid film solar-assisted concentrator.Measured maximum evaporation rate and productivity were between 1.3 and 1.5 kg m⁻² h⁻¹, and 80 kg m⁻² over a 7 day experimental period respectively which was about a third better performance compared with a shallow basin horizontal concentrator. Measurements were in good agreement with model predictions: within 2 °C at the peak and 4 °C at the lowest evaporation, and 0.2 kg m⁻² h⁻¹ for evaporation rates during the peak evaporation periods of the day when compared with independent data sets. Cumulative evaporation rates were from 75 to 85 kg m⁻² for the tilted concentrator model and 60 to 65 kg m⁻² for the horizontal concentrator model after 7 days. The tilted concentrator yielded productivity and efficiency that were 33% higher than the horizontal concentrator according to the experimental result for the same period and location.     

导读

《艺者匠心录》的前两篇文章是从传统的博物学角度对于野生动物栖息地的研究。第三篇文章同样也研究自然区域,却是从社会科学和文化地理学的角度切入的。对于许多研究人员来说,自然科学与社会科学区别明显,但对于那些在两个领域都做研究的学者来说,相似之处多于差异。     

A dose response study of hepatitis A vaccine in healthy adults who are > or = 30 years old and weigh > or = 77 kg

The dose response relationship of 25-, 50-, and 100-U doses of an inactivated hepatitis A vaccine was examined in 358-seronegative volunteers in a 2-dose schedule. The 50-U and 100-U groups had statistically significantly higher seroconversion rates than the 25-U group at weeks 2, 4, 8, and 24. Seroconversion was statistically significantly greater for the 100-U compared with the 25- and 50-U doses 2 weeks after the first injection but was not significantly different by 4 weeks after the first injection in the 50- and 100-U dose groups. After 2 injections, all subjects in all groups seroconverted. The vaccine was well tolerated at all dosage levels.     

Collective versus individual induction with single versus multiple hypotheses.

Four-person cooperative groups and 4 independent individuals solved rule induction problems by proposing 1, 2, or 4 hypotheses per trial while selecting the same amount of evidence per trial. Groups performed at the level of the best individuals and better than the 2nd-best, 3rd-best, and 4th-best individuals for both correct hypotheses and nonplausible hypotheses. Increasing the number of proposed hypotheses from 1 to 2 to 4 did not increase correct hypotheses but increased nonplausible hypotheses. Transition probabilities from hypotheses on trial t to t?+?1 indicated superior performance for the groups and best individuals for each of positive and negative hypothesis tests followed by examples and nonexamples; once the groups and best individuals proposed the correct hypothesis, they were more likely to continue to propose it than the other individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adsorption of Pentane Insoluble Organic Matter from Oilsands Bitumen onto Clay Surfaces

The effectiveness of commercial oilsands separation processes relies on the water wettability of the solids. Consequently, the interaction between the mineral and organic matter types present in oilsands is of interest. In this work, we report results related to the adsorption of a pentane insoluble fraction from bitumen on kaolinite and illite, the major clay types present in oilsands. We determined adsorption from toluene solution by illite and kaolinite and use a combination of spectroscopic techniques to probe the organic coated clay surfaces to different depths. The results are compared with similar data for equivalent natural fractions from oilsands.     

Speed of information processing as a mediator between age and free-recall performance.

A combined experimental and individual differences approach was used to investigate the mediating role of task-specific and task-independent speed of information processing measures in the relationship between age and free-recall performance. 36 younger adults (mean age 21 yrs) and 36 older adults (mean age 73 yrs) participated. Participants were required to encode 3 lists of words for immediate recall, by rehearsing the words aloud, once, twice, and 3 times. Participants' speed of information processing was assessed by 3 measures: rehearsal time, articulation speed, and scores on the Digit Symbol Substitution Test (DSST). Working memory was also assessed by a backward word-span measure. As predicted, younger adults recalled more words after rehearsing words 3 times rather than once, whereas older adults' recall did not increase with increasing numbers of rehearsals. Younger adults were faster on all speed-of-processing measures and had higher backward word span than did older adults. Task-independent speed of processing, measured by DSST scores and articulation speed, mediated the relationship between age and free recall. Scores on the DSST appear to reflect a fundamental difference between younger and older adults that influences recall performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)