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.     

Playing chess unconsciously.

Expertise in a certain stimulus domain enhances perceptual capabilities. In the present article, the authors investigate whether expertise improves perceptual processing to an extent that allows complex visual stimuli to bias behavior unconsciously. Expert chess players judged whether a target chess configuration entailed a checking configuration. These displays were preceded by masked prime configurations that either represented a checking or a nonchecking configuration. Chess experts, but not novice chess players, revealed a subliminal response priming effect, that is, faster responding when prime and target displays were congruent (both checking or both nonchecking) rather than incongruent. Priming generalized to displays that were not used as targets, ruling out simple repetition priming effects. Thus, chess experts were able to judge unconsciously presented chess configurations as checking or nonchecking. A 2nd experiment demonstrated that experts' priming does not occur for simpler but uncommon chess configurations. The authors conclude that long-term practice prompts the acquisition of visual memories of chess configurations with integrated form-location conjunctions. These perceptual chunks enable complex visual processing outside of conscious awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gait generation considering dynamics for artificial segmented worms

This paper deals with terrestrial worm-like locomotion systems living in a straight line. They are modeled as chains of mass points having ground interaction via spikes which make the velocities unidirectional. A method is presented to construct gaits with any desired time pattern of resting mass points (which are acted on by the propulsive forces). Taking the dynamics into consideration, conclusions about the choice and shift of gaits in connection with actuator data are given.     

Fire resistance of wood treated with a cationic silica sol

Wood was treated with the cationic silica sol (CSS) Levasil 200S and dried at various temperatures (room temperature, 40, 60, 80 and 103 °C). A water leaching test revealed fixation of the silica in wood even after drying at room temperature. Maximum cross sectional swelling of the specimens decreased from 15.6 % (untreated control) to 13.0 %, when treated wood was dried at 103 °C; cell wall bulking values were also negative (?2.3 %), indicating a thermal degradation of the cell wall polymers catalyzed by the CSS. Penetration of the CSS into the cell wall did not occur. A simple flammability test revealed increased fire resistance of the treated wood. Mass loss and velocity of mass loss as well as burning time were reduced; glowing of the formed charcoal was completely prevented. The effectiveness increased with increasing weight percent gain of the CSS in the wood. Thermo gravimetric analysis under nitrogen atmosphere displayed only minor reduction in the initial temperature of thermal decomposition for wood treated with CSS as compared to the control. In the presence of oxygen the resulting charcoal showed comparable thermal behaviour to the control. The yield of charcoal after pyrolysis was increased to a minor extent (from 19.9 to 23.0 %), indicating that the release of combustible gases was hardly reduced. The mode of action of enhanced fire resistance due to CSS-treatment is discussed.     

Criteria for the complementary allocation of functions in automated work systems and their use in simultaneous engineering projects

A crucial step in any system design concerns the allocation of functions between human and machine. In simultaneous engineering, function allocation is potentially an issue both in product design — if the product is a technical system itself — and in process design. It is argued that well-founded function allocation decisions in relation to the production process are of particular importance in simultaneous engineering as less and less time is allowed for compensation for inadequate or missing decisions which will impede production effectiveness. The focus of recent methods for the allocation of functions is to operationalize the concept of complementarity, meaning to provide guidelines for complementing humans by technical systems instead of replacing them gradually as technical systems become more and more sophisticated. As systems design becomes more complex, involving more and faster changes and placing higher demands on engineers as well as system operators, the idea of complementary gains importance because it stresses the need to allocate functions in a way that supports human control over the production process and the development and maintenance of the necessary skills. Looking at existing methods and instruments for the complementary allocation of functions, one is at first sight confronted with a multitude of criteria for complementarity, but to date neither a fixed set of criteria, comparable to software usability criteria, nor widely accepted methods for their measurement exist. As part of a research project concerned with the development of guidelines whose objective is to assist engineers in designing work systems according to the complementarity principle, four central criteria for complementary function allocation were identified: dynamic coupling, process transparency, human decision authority, and flexibility. These criteria and their application in a design process are illustrated by means of a case study and discussed in terms of other approaches to complementary design as well as their use for simultaneous engineering projects.

Relevance to industry

Adequate allocation of functions between human and machine is crucial for the effectiveness of any production system. With more complex and faster design processes in simultaneous engineering projects, the need for methods supporting prospective analysis and design of human-machine systems has increased even more. The article presents such a method based on the principle of complementarity between human operator and technical system and illustrates its use by means of a case study.     

Comparison between lasers isolated by oxygen implantation and SiO2isolated stripe lasers

GaAs/GaAlAs DH lasers isolated by an SiO2layer on top of the p-contacting layer are compared to DH lasers in which the isolation is maintained by an isolating the O+ -implanted layer within the n+- substrate. Measurements were performed on four O+ isolated lasers and five SiO2isolated lasers with the same composition and thickness of active and upper confinement layers. Threshold currents of both groups were very similar, whereas the O+ -implanted lasers showed superior thermal resistances by a factor of 2. Thermal resistances were measured by the shift of the lasing spectra with power dissipation.     

Einsatzpotenziale von XML in Business-Intelligence-Systemen

This article describes the actual applications of XML in the context of Business- Intelligence-Systems (BI). The potentials and synergies of XML and BI will be emphasized.

1. XML applications can be found within all levels of BI-systems.
2. The application of core-standards will be introduced as well as the possibilities of BI specific-standards.
3. The discussion of the impact of XML for BI-systems follows along the dimensions: externalisation, integration, standardisation and rationalization.

     

Design of near-field holographic optical elements by grating matching

A new method for designing holographic optical elements is presented. The method is based on matching the grating-spacing profile of the recording light interference pattern to the desired grating-spacing profile. We show that for designing near-field holograms, in which the optical images involved are close to the hologram aperture, the grating-matching technique is superior to the well-established aberration-balancing method introduced by Latta [Appl. Opt. 10, 609 (1971)].     

Cuprates and Ruthenates: Similarities and Differences

There is growing evidence that the p-wave superconductivity of Sr₂RuO₄ occurs primarily in the planar -band. Thus the minimum model for both cuprates and ruthenates is a single active band with onsite Coulomb interactions. Recent renormalization group analysis shows that such a model can show singlet d-wave or triplet p-wave pairing. The energy of the van Hove singularity in the band and the shape of the Fermi surface are the decisive factors at weak to moderate interaction strengths.