Disc filtration for separation of flocs from a moving bed bio-film reactor.

A Discfilter with 10 and 18 microm filter openings, respectively, was placed in parallel to a flotation plant for separation of biological flocs from a post-denitrifying Kaldnes Moving Bed Process, the last treatment step at the municipal wastewater treatment plant at Sj?unda, Malm?, Sweden. The effluent concentrations from the 10 and 18 microm filter were 2-5 and 2-8 mg SS L(-1), respectively, which is comparable to, or better than, the flotation plant. Comparison with experiences from activated sludge plants shows that the Discfilter works especially well after the Kaldnes process. Particle size distribution (PSD) studies show that particles larger than the filter openings of 10 and 18 microm are separated with approximately 90% efficiency, whereas most of the smaller particles pass the filter. This fact indicates that the major particle separation mechanism is physical blocking. These findings point to the possibility of improving the prediction of the separation efficiency by combining measurements of turbidity and suspended solids with particle size analysis.     

Efficient Engineering and Production Concepts for Products in Regulated Environments – Dream or Nightmare?

Manufacturing of chemical‐pharmaceutical products is moving increasingly fast on a global scale. Therefore, developing and starting up production facilities fast, with high quality, and at reasonable costs has become extremely challenging. Engineering concepts like modularization, standardization and simultaneous/parallel engineering are discussed as methods for speeding up process design and filing for regulatory approval. Transfer from batch to continuous operation mode of production is pointed out as the key‐issue in such strategies.     

Integration of Ultrafiltration Unit Operations in Biotechnology Process Design

A stepwise process design approach is proposed to model membrane unit operations generally in combination with experimental model parameter determination in laboratory scale, in order to predict the purification performance a priori by simulations for multicomponent mixtures. The development of a rigorous model for an ultrafiltration membrane is described. In conceptual process design, the degree of comprehension of all unit operations integrated have to be almost identical to be able of any consistent process proposal taking equipment‐related fluid‐dynamical and kinetic nonidealities besides thermodynamical feasibility into account. Therefore, a process model, combining the most limiting factors within one mathematical model, is established and various filtrations are carried out with a binary solution for validation. Additionally, a standard laboratory equipment is instituted for logging time‐dependent concentration profiles. The practicability of the proposed procedure is proven in order to design and integrate ultrafiltration membranes into total purification processes.     

Examination of Interpenetrating Polymer Networks of Polyurea in Silicone Molds Arising during Vacuum Casting Processes

We present an in-depth investigation of the aging effects in silicone molds for vacuum casting processes. Their lifetime is limited to a few production cycles due to contamination with the diisocyanate component of polyurethane casting materials. Using thermogravimetric analysis measurements, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and helium-ion-microscopy the chemical and physical mechanisms of the aging process have been identified. It has been shown that a diffusion process of diisocyanate into the cavity surface leads to the formation of interpenetrating polymer networks of polyurea derivatives in silicone rubber. This has been proven by extracting and analyzing polyurea of low molecular weights from the silicone.     

Self-evaluation of abilities: Accurate self-assessment versus biased self-enhancement.

In Study 1, 170 volunteers (mean age 24.2 yrs) chose among 8 forms of a cognitive abilities test that varied in their diagnosticity of success, diagnosticity of failure, and difficulty. In accordance with the self-assessment view, test choice was found to be positively related to diagnosticity of success and, to a lesser extent, diagnosticity of failure. Test choice was also dependent on the interaction of diagnosticity and difficulty in a manner that was more consistent with the self-assessment view. In a 2nd study that provided more precise measurement of perceived diagnosticity and expected success, data from 40 undergraduates indicate that the motives for self-assessment and self-enhancement were each reliably related to task preference. Of the two, self-assessment motivation was a stronger determinant of task preference. Results suggest that task choice is governed largely by a concern for accurate self-appraisal and that current models may require revisions that take into account the less-than-accurate appraisal of diagnosticity. (37 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Comparison of power rates for combined probability procedures: A simulation study.

Compared the power of 6 techniques (adding logs, adding p's, mean p, adding z's, mean z, and adding t's) for combining the significance levels from independent tests of a common conceptual hypothesis using simulation procedures. Results indicate that for large numbers of studies to be combined, all procedures provided comparable power. The techniques varied in their ease of computation, however, making some procedures more preferrable under certain conditions. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examination of the Aging Effects of Silicone Molds During Vacuum Casting Processes via Scanning Electron Microscopy

We present an in-depth investigation of contaminated silicone molds by use of scanning electron microscopy, that provides additional insight into the aging process of the molds. The molds lifetime in vacuum casting processes of polyurethane is limited due to contamination with the diisocyanate compound of the PUR resin. SEM investigations, combined with FIB cross-sections and EDX measurements show that three different types of particles are distributed in the contaminated silicone matrix. The particles differ in shape and size, with a range from 50 nm to 50 µm. This explains the loss in transparency and the hardened haptics of contaminated molds.