Nitrification parameter measurement for plant design: experience and experimental issues with new methods.

Nitrification kinetics are important for process design, optimization, and capacity rating of activated sludge wastewater treatment plants. A Water Environment Research Foundation (WERF) project on Methods for Wastewater Characterization in Activated Sludge Modeling (WERF, 2003) focused significantly on the development of procedures for measuring the nitrifier maximum specific growth rate, micro(AUT). In addition, the importance of (and lack of data for) the nitrifier decay rate, b(AUT), was identified. This paper describes three bench-scale methods for measuring micro(AUT): the Low F/M SBR, Washout and High F/M methods. During the WERF project, the importance of pH and temperature control was investigated briefly; this paper summarizes further experimental work performed to address these issues. A summary of micro(AUT) measurements in a number of locations and using the different measurement techniques is provided.     

High temperature oxidation mechanism of dilute copper aluminium alloys

Dilute copper-aluminium alloys were oxidized in air from 700 to 1000 °C. Two distinctive behaviours were observed: alloys with at least 3 wt% aluminium showed excellent oxidation resistance in the whole temperature range. Alloys with 2 wt% or less aluminium exhibited good oxidation resistance up to 800 °C; but as the temperature was further increased, the oxidation rate of these alloys increased and became comparable to that of pure copper. A kinetic model was developed to explain the oxidation behaviour and indirectly determine the amount of dissolved oxygen in the alloys tested. It was found that the oxygen dissolved in alloys with up to 2 wt% Al exceeded its solubility limit in copper, whereas the dissolved oxygen in alloys with higher aluminium contents was below the solubility limit. This difference may account for the significantly different oxidation resistance.     

Review of Revitalizng retirement: Reshaping your identity, relationships, and purpose.

Reviews the book, Revitalizng retirement: Reshaping your identity, relationships, and purpose by Nancy K. Schlossberg (2009). Therapists, counsellors, and life coaches working with older middle-age adults will find this handbook to happiness in retirement a useful working tool. The author introduces the book by stating that some content resembles notes she resurrected from a freshman undergraduate lecture on personal development; accordingly, both the format and the issues discussed in this book generalise to life span motivational needs, but the intended focus is on the transition to retirement. As a result, this book would make a useful tool for a support group or workshop on psychosocial transitions in postemployment life, with some limitations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The reduction of Tokyo and Sinter 75 nickel oxides with hydrogen

Industrial Tokyo and Sinter 75 nickel oxides were reduced with 35 and 80% volume hydrogen-argon mixtures between 350 and 1000 °C in a TGA apparatus. Several abnormalities were observed. At low temperature and in 35% H₂, an incubation period was observed. As the temperature was increased the rate of reduction increased up to some temperature, following which a decrease in the reaction rate was observed, which again was followed by an increase in the rates as the temperature exceeded 900 °C. It was found that reduction kinetics of these oxides strongly depend on the morphological features of the oxides. It became clear that the shrinking core model was not applicable and instead the kinetic parameters were assessed by the grain model.     

Inflow shortages in deregulated power markets — Reasons for concern?

In many countries hydropower constitutes a large share of the electricity producing capacity. In the earlier regulated electricity markets, production capacities exceeded demand due to security of supply concerns. The present deregulated markets base investments upon profitability alone, and security of supply issues are claimed to be less important. Market operators trust the pricing mechanism in competitive markets to clear. Then low inflow constitutes a less problem. Several markets, both under regulated and deregulated regimes, have faced serious droughts. Some of them have experienced problems with market clearance (Chile, Brazil, California) while other markets functioned well (The Nordic market). Important features to the market response are the flexibility of demand, the pattern of inflow shortage, the storage capacities, the possibility of trade between regions with different production technologies, and the market design and concentration. We apply an empirical based market model to simulate the effects under two inflow shortage scenarios in an international market with combined hydro and thermal capacities and restricted transmission capacities. We compare the scenarios with actual events and show that the model and the real market outcome are comparable. The simulations do not reveal any problems with the functioning of the market, which should calm down the anxiousness about security of supply in deregulated markets with stochastic energy supply.     

Mixed effect modeling of sumatriptan pharmacokinetics during drug development. I: Interspecies allometric scaling

A sample of 22 subjects was studied from a population of adults who had suffered from bacterial meningitis in childhood. Audiovestibular, oculomotor and neuropsychological investigations were performed and quality of life was assessed. An age-matched control group of 20 subjects was recruited. In the meningitis group, nine subjects had abnormal pure tone audiograms. One was previously undiagnosed and a progression was found in four. There was an overrepresentation of subclinical vestibular pathology (6 out of 9 (67%)) in this group. Audiovestibular test results showed a peripheral pattern and oculomotor tests were normal. The quality of life scores of those with hearing loss were significantly higher than those in the control group. Neuropsychological tests of brain dysfunction were abnormal in six out of 22 (27%) who had recovered from meningitis. The prevalence of such dysfunctions was not related to audiovestibular disorder. The quality of life scores of those with brain dysfunctions were similar to those of the control group. The findings of reduced auditory memory and tone level perception in four out of 22 (18%), suggest that lesions of central auditory pathways may follow from bacterial meningitis. The results support the idea that inner ear damage is the major cause of hearing loss after bacterial meningitis. Despite the absence of brainstem involvement, central nervous system lesions with disturbed auditory processing and language functions can be of significance. The high frequency of discrete brain dysfunctions indicate that a thorough neuropsychological investigation is required after bacterial meningitis.