Energy from streaming current and potential

It is investigated how much energy can be delivered by a streaming current source. A streaming current and subsequent streaming potential originate when double layer charge is transported by hydrodynamic flow. Theory and a network model of such a source is presented and initial experimental results are given, showing a supplied power of 20 nW obtained by a pressure difference of 1 atm over a glass porous plug, using a 1-mM KCl solution. It is indicated how the rather low mechanical-to-electrical energy conversion efficiency can be increased

Negotiating the meaning of film for intercultural pastoral work: Tsotsi and the cry for humanity

Acknowledging the fact that stories play a very important role in Africa, it is a given that, with the emphasis on the narrative accent, the medium of film is regarded as an important expression of meaning giving. The award wining movie ''Tsotsi'', by the director Gavin Wood and based on the novel with the same title by Athol Fugard, portrays contemporary South Africa revealing heartbreaking realities of poverty, HIV and / or AIDS and crime. In exploring the fact that films from other countries could be considered as prime vehicles for cultural and religious exploration, not only in content and form, but also in audience reception, the proposed ABDCE-research paradigm for intercultural pastoral work is followed. Accordingly to this paradigm, and concurrent to the narratives portrayed in film, the movements of Action, Background, Development, Climax and Ending could constitute a narrative research paradigm and epistemology. In following this methodology the focus in the paper will be on exploring and describing the background that informed the development of the movie ''Tsotsi'' within the South African context. In the practice of the development of a form of practical wisdom which values the stories of people and communities, it is described how the pastoral paradigm portrayed by film could assist people to give meaning to their humanity

Nanotechnology for membranes, filters and sieves

This mini-review is dedicated to the use of nanotechnology for membranes, filters and sieves. With the advent of nanotechnology researchers have acquired an unprecedented freedom to sculpt device geometry almost down to the molecular scale. Such structures can now replace the gels, membranes and sieves of random pore structure that are commonly used in such separations. In this mini-review we want to highlight the impact that this development has had in the area of separation by filtering and sieving, where exciting developments are taking place. To do this we will first present the basic phenomena that determine separation in these devices, together with some historical background. Subsequently we will look at the micro- and nanomachined membranes, filters and sieves that have been manufactured in the past few years, and highlight advances resulting from the use of nanotechnology. In particular, the ability of nanotechnology to produce spatially anisotropic sieving structures suitable for continuous flow operation is seen as a new and exciting development. The invention of structures that sculpt hydrodynamic flow lines in order to perform continuous filtering is another important development. In general continuous flow operation is desirable in nanoscale systems since sampling (either of a detection signal or of the separated substances) can be time-integrated, thus improving the detection limit

Proteomics-on-a-chip for Biomarker discovery

In proteomics research still two-dimensional gel electrophoresis (2D-GE) is currently used for biomarker discovery. We applied free flow electrophoresis (FFE) separation technology combined with biomolecular interaction sensing using Surface Plasmon Resonance (SPR) imaging in an integrated proteomics-on-a-chip device as a proof of concept for biomarker discovery

Vroue se belewenis van eensaamheid na die verlies van ’n lewensmaat: ’n Beskrywing van narratiewe pastorale betrokkenheid

Women’s experience of loneliness after the loss of a spouse: A description of a narrative pastoral engagement.In this contribution the phenomenon of loneliness experienced by women after the loss of a spouse is explored. The purpose of this research is to clarify and interpret the experience of loneliness as well as its occurrence and meaning. Implications are examined according to the way in which it is experienced. The research is founded in practical theology and researched from within a postmodernity paradigm, with a social constructionist discourse as epistemological point of departure. By employing the qualitative research approach, different courses of action are used for collecting data for the research. Principles underpinning participatory action research are employed as part of a qualitative research method. The research is further informed by using mechanisms of the narrative approach which correlate well with the principles of participatory action research. This conversational approach is used to explore and describe meaningful alternatives to cope with loneliness. The main findings of the research are that women do experience loneliness after the loss of a spouse and that they have a need for an attachment figure to help them to cope with the loneliness

Flash suppression and flash facilitation in binocular rivalry

We show that previewing one half image of a binocular rivalry pair can cause it to gain initial dominance when the other half is added, a novel phenomenon we term flash facilitation. This is the converse of a known effect called flash suppression, where the previewed image becomes suppressed upon rivalrous presentation. The exact effect of previewing an image depends on both the duration and the contrast of the prior stimulus. Brief, low-contrast prior stimuli facilitate, whereas long, high-contrast ones suppress. These effects have both an eye-based component and a pattern-based component. Our results suggest that, instead of reflecting two unrelated mechanisms, both facilitation and suppression are manifestations of a single process that occurs progressively during presentation of the prior stimulus. The distinction between the two phenomena would then lie in the extent to which the process has developed during prior stimulation. This view is consistent with a neural model previously proposed to account for perceptual stabilization of ambiguous stimuli, suggesting a relation between perceptual stabilization and the present phenomena