Combined Wettable/Non‐wettable Filter for Mist Purification

Previous studies by Agranovski and Braddock [1] show that wettable filters are very efficient at collecting small liquid aerosols. However, a major problem associated with wettable filters is the breakthrough process associated with the destruction of film covering the fibres, and the removal of relatively large droplets by the carrier gas passing through the rear surface of the filter. A non‐wettable filter is relatively efficient at collecting large droplets and discarding them down its front face [2]. These two types of filters can be combined in layers to make use of these distinctive properties. The best arrangement is where the carrier gas passes first through the wettable filter, and then through the non‐wettable filter. Where there is a contact between the two filters, interface effects assist the filtration and filter system drainage. The filtration mechanisms are enhanced when the filter box is tilted so that gravity partially opposes the drag forces on the liquid in the filter. In the current paper, the results of experimental analysis of combined filtration systems are presented, and further steps towards industrial design are discussed.     

Impact of Metal Ridging on the Fluidization Characteristics of FCC Catalyst

Minimum fluidization and bubbling velocities were used to compare the fluidity of FCC catalyst sourced from various refineries. It was found that fluidity characteristics of the catalyst of the same original type change after some period of use in the FCCU. Under closer examination using Scanning Electron Microscopy (SEM), large surface ridging of metal contaminates, was identified on the used catalyst. Mild bubbling attrition tests were conducted, and it was found that all of the catalyst experienced an increase in fluidity. Using total levels of iron, it was discovered that it is the quantity of metal ridging that is important and not the total levels of metals which influence fluidizing characteristics. This work provides insight into what causes changes to fluidizing characteristics inside an operation FCCU.     

The New Morris Method: an efficient second-order screening method

The New Morris Method was proposed by Campolongo and Braddock [Reliab. Engng Syst. Saf. 64 (1999) 1] as an extension of the Morris Method [Technometrics 33 (1991) 161] to include estimation of two-factor interaction effects. An undetected programming error prevented Campolongo and Braddock from appreciating the efficacy of the method. Testing on an analytic function reveals that the method is more powerful and efficient than previously thought.     

High-power 10%-tuning-bandwidth varactor-controlled impatt oscillator/amplifier

A simple electronically tuned c.w. GaAs impatt/varactordiode oscillator/amplifier circuit is described which can be tuned over a 10% bandwidth at mid-X-band frequencies at a power level greater than 0.5 W as an oscillator, and greater than 0.8 W at the 6 dB-gain level as a reflection amplifier. Unambiguous electronic tuning without power jumps, frequency hops or `out-of-band? oscillations has been achieved by paying special attention to the circuit design.     

Effects of hydrogen on phase stability of ytterbium doped strontium cerates

The effect of hydrogen on the phase stability of both SrCe_0.95Yb_0.05O_3 − α, (SCYb-5) powder and disk samples in both dry and wet hydrogen atmospheres was investigated. It was found that decomposition of the perovskite phase was especially evident in the disk samples treated in a dry hydrogen atmosphere, probably due to reduction of the tetravalent cerium ions to trivalent cerium ions in the sample. It was interesting to find that the extent of the decomposition of the perovskite phase was most influenced by the status (i.e. either disk or powder form) of the SCYb-5 samples, rather than the temperature or the extent of the reducing atmospheres. The findings of this study indicate that relaxation kinetics may play an important role in the phase stability of perovskite materials.     

Particle Bounce During Filtration of Particles on Wet and Dry Filters

This paper experimentally examines the bounce and immediate re-entrainment of liquid and solid monodisperse aerosols under a stable filtration regime (precake formation) by wet and dry fibrous filters. PSL and DEHS were the solid and liquid aerosols, respectively, used in four monodisperse sizes of 0.52, 0.83, 1.50, and 3.00 w m. Three different fibrous filters were used to filter the aerosol streams, and the efficiency of the filtration process for each aerosol type under dry and wet regimes was measured. It was found that the solid particles generally exhibited a lower fractional filtration efficiency than liquid particles, although this difference decreased in the smaller size fractions. The difference between solid and liquid efficiencies was found to be greatest in the 1.5 w m size range. As particle sizes of liquid/solid aerosols and filtration parameters were similar, this difference is most likely to be due to the effect of particle bounce and or immediate re-entrainment occurring inside the filter, with the greater efficiency of filtration of the liquid particles being due to their greater capacity to plastically/elastically deform in order to absorb the impact forces. However, for the wet filtration regime (each fibre of the filter was coated by a film of water), no significant difference in filtration efficiency was detectable between solid and liquid aerosols. Therefore, the conclusion can be drawn that the either the bounce effect of the particles is inhibited by the liquid film, or the filtration conditions in the wet filter are so different that the aerosol properties are less significant with respect to capture.     

Psychologists' knowledge and attitudes about fetal alcohol syndrome, fetal alcohol spectrum disorders, and alcohol use during pregnancy.

Do you have adequate knowledge of the hallmarks of fetal alcohol syndrome and fetal alcohol spectrum disorders? Can you identify pregnant women who are at risk for having a child with the disorder? A large random sample survey of American Psychological Association members uncovered large deficits in psychologists' knowledge about the diagnosis, treatment, and prevention of these problems. The authors report accurate information about these damaging disorders and identify the errors most commonly demonstrated by those surveyed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental characterisation of avalanche-diode reflection amplifiers and locked oscillators

Qualitative experimental results are presented for a silicon IMPATT diode on the distinction between the undercoupled quenched oscillator, optimised oscillator, locked oscillator, stable amplifier, in relation to the gain, linearity and saturation power. The results are consistent with a nonlinear interpretation of the equivalent diode conductance.