Achieving flue gas desulphurization with membrane gas absorption

Membrane gas absorption (MGA) is an efficient and flexible way to carry out gas-liquid (G-L) contacting operations with hollow fibre membranes. The main advantages of membrane gas absorption over conventional G-L contactors is the compactness and low weight of the installation, the standard modular construction elements and the flexible operation. Gas and liquid flow can be controlled independently in the MGA process, which makes operation over a wide range of liquid and gas flow rates possible. In a MGA installation no entrainment, flooding, channelling or foaming occurs. Rob Klaassen and Albert E Jansen, TNO Environment, Energy and Process Innovation, discuss the principle of this technology, the benefits of newly developed membrane modules and their potential applications.     

Guided architecture trade space exploration: fusing model-based engineering and design by shopping

Software and Systems Modeling - Advances in model-based system engineering have greatly increased the predictive power of models and the analyses that can be run on them. At the same time, designs...     

The formation of cuprous oxide films on α-brass stress-corrosion fracture surfaces

A study has been made of the nature of the fracture surface of α-brass specimens after failure by stress-corrosion cracking in pH 7·2 Mattsson's solution. The yellow colour of the stress-corrosion fracture surface points to a possible inadequacy in the “tarnish-rupture” model of the mechanism of this instance of stress-corrosion. The techniques of cathodic reduction and chemical dissolution have been used to remove any oxide present on the original fracture surface. On subsequent re-immersion in pH 7·2 Mattsson's solution, the stress-corrosion fracture surface remains untarnished, whereas the mechanical fracture surface rapidly acquires a black tarnish film. Comparison of plateau lengths obtained on further cathodic reduction has shown that for equivalent times of re-immersion, a much thicker film forms on the mechanical fracture region than on the stress-corrosion region of the fracture surface. The experimental results are interpreted as being inconsistent with the “tarnish-rupture” model but consistent with a stress-corrosion mechanism involving dezincification at the crack tip.     

Environmentally-induced cracking of magnesium

Slow strain rate tensile tests have been carried out on commercially pure and high purity magnesium specimens in air and in de-aerated, pH 10, 10^?3 M Na₂SO₄ solution under different environmental conditions. The results of these tests have been supplemented by studies of the failed specimens using optical metallography and scanning electron fractography. It is shown that under certain environmental conditions magnesium is susceptible to hydrogen embrittlement and environmentally-induced cracking in Na₂SO₄ solution. The source of the hydrogen, even under anodic polarization, is the local action cathodic reaction. Atomic hydrogen can only enter, and embrittle, the metal matrix at active, bare, passive-film-free pit walls. Therefore if pitting is promoted by anodic polarization cracking is more severe; conversely if pitting is prevented by cathodic polarization, embrittlement and cracking are not observed. Atomic hydrogen produced by cathodic polarization is prevented by the presence of the Mg(OH)₂ passive film from entering the metal and causing embrittlement; furthermore even at a strain rate of5.7 × 10^?6 s^-1passivation is sufficiently rapid to prevent entry of hydrogen during tensile testing of cathodically polarized specimens. Depending on the grain size and purity the embrittled magnesium specimens exhibit either a completely transgranular quasicleavage fracture surface morphology or a mixed brittle intergranular and quasi-cleavage transgranular fracture surface morphology. Possible mechanisms for the hydrogen-induced cracking are discussed briefly in light of the demonstrated reversibility of hydrogen uptake. It is suggested that hydrogen embrittlement and cracking may account for spalling and disintegration of magnesium anodes and may contribute to the negative different effect.     

Ready to preorder: The case of weak process semantics

Recently, Aceto, Fokkink and Ingólfsdóttir proposed an algorithm to turn any sound and ground-complete axiomatisation of any preorder listed in the linear time-branching time spectrum at least as coarse as the ready simulation preorder, into a sound and ground-complete axiomatisation of the corresponding equivalence—its kernel. Moreover, if the former axiomatisation is ω-complete, so is the latter. Subsequently, de Frutos Escrig, Gregorio Rodríguez and Palomino generalised this result, so that the algorithm is applicable to any preorder at least as coarse as the ready simulation preorder, provided it is initials preserving. The current paper shows that the same algorithm applies equally well to weak semantics: the proviso of initials preserving can be replaced by other conditions, such as weak initials preserving and satisfying the second τ-law. This makes it applicable to all 87 preorders surveyed in “the linear time-branching time spectrum II” that are at least as coarse as the ready simulation preorder. We also extend the scope of the algorithm to infinite processes, by adding recursion constants. As an application of both extensions, we provide a ground-complete axiomatisation of the CSP failures equivalence for BCCS processes with divergence.     

80 million tiny images: a large data set for nonparametric object and scene recognition

With the advent of the Internet, billions of images are now freely available online and constitute a dense sampling of the visual world. Using a variety of non-parametric methods, we explore this world with the aid of a large dataset of 79,302,017 images collected from the Internet. Motivated by psychophysical results showing the remarkable tolerance of the human visual system to degradations in image resolution, the images in the dataset are stored as 32 x 32 color images. Each image is loosely labeled with one of the 75,062 non-abstract nouns in English, as listed in the Wordnet lexical database. Hence the image database gives a comprehensive coverage of all object categories and scenes. The semantic information from Wordnet can be used in conjunction with nearest-neighbor methods to perform object classification over a range of semantic levels minimizing the effects of labeling noise. For certain classes that are particularly prevalent in the dataset, such as people, we are able to demonstrate a recognition performance comparable to class-specific Viola-Jones style detectors.     

Contact through canvas: an entertaining encounter

When meeting someone new, the first impression is often influenced by someone’s physical appearance and other types of prejudice. In this paper, we present TouchMeDare, an interactive canvas, which aims to provide an experience when meeting new people, while preventing visual prejudice and lowering potential thresholds. The focus of the designed experience was to stimulate people to get acquainted through the interactive canvas. TouchMeDare consists of a flexible, opaque canvas, which plays music when touched simultaneously from both sides. Dynamic variation of this bodily contact is reflected through real-time adaptations of the musical compositions. Two redesigns were qualitatively and quantitatively evaluated and a final version was placed in the Lowlands Festival as a case study. Evaluation results showed that some explanation was needed for the initial interaction with the installation. On the other hand, after this initial unfamiliarity passed, results showed that making bodily contact through the installation did help people to get acquainted with each other and increased their social interaction.     

A three phase serpentine micro electrode array for AC electroosmotic flow pumping

A new three-phase electrode array with a serpentine electrode is designed and prototyped using PolyMUMPs process for micro flow pumping. Numerical model of the micropump has been developed using COMSOL Multiphysics™. Experimental testing is conducted and time-averaged flow velocities from testing and simulation agree well. Peak time-averaged flow velocity of 270 μm/s is achieved at 30 Hz using ethanol.     

Visualization of diversity in large multivariate data sets

Understanding the diversity of a set of multivariate objects is an important problem in many domains, including ecology, college admissions, investing, machine learning, and others. However, to date, very little work has been done to help users achieve this kind of understanding. Visual representation is especially appealing for this task because it offers the potential to allow users to efficiently observe the objects of interest in a direct and holistic way. Thus, in this paper, we attempt to formalize the problem of visualizing the diversity of a large (more than 1000 objects), multivariate (more than 5 attributes) data set as one worth deeper investigation by the information visualization community. In doing so, we contribute a precise definition of diversity, a set of requirements for diversity visualizations based on this definition, and a formal user study design intended to evaluate the capacity of a visual representation for communicating diversity information. Our primary contribution, however, is a visual representation, called the Diversity Map, for visualizing diversity. An evaluation of the Diversity Map using our study design shows that users can judge elements of diversity consistently and as or more accurately than when using the only other representation specifically designed to visualize diversity.