The lowest crossing in 2D critical percolation

We study the following problem for critical site percolation on the triangular lattice. Let A and B be sites on a horizontal line e separated by distance n. Consider, in the half-plane above e, the lowest occupied crossing R from the half-line left of A to the half-line right of B. We show that the probability that R has a site at distance smaller than m from AB is of order (log (n/m))^{-1}, uniformly in 1 <= m < n/2. Much of our analysis can be carried out for other two-dimensional lattices as well.Comment: 16 pages, Latex, 2 eps figures, special macros: percmac.tex. Submitted to Annals of Probabilit

Non-Extensive Bose-Einstein Condensation Model

The imperfect Boson gas supplemented with a gentle repulsive interaction is completely solved. In particular it is proved that it has non-extensive Bose-Einstein condensation, i.e., there is condensation without macroscopic occupation of the ground state (k=0) level

µTransparent insulating channels as components for miniaturized chemical separation Devices

Currently, miniaturized devices that apply electro osmotic pumping or electrophoretic separations are mostly constructed by etching small insulating channels for supply and separation on glass substrates. In principle, silicon is a superior construction material in terms of inertness and design flexibility. However, because of its semiconducting properties, the use in high voltage applications like the ones mentioned above is quite limited. In this paper, the use of μTransparent Insulating Channel (μTIC) technology is demonstrated as a standard procedure to manufacture miniaturized analytical separation devices. This technique, μchannels having extremely thin, transparent and insulating walls can be fabricated. An overview of the impact of this technology is given, showing the advantages of a fabrication technology that is as flexible as silicon technology for the fabrication of μTAS or “lab on a chip” devices. The following basic technology and control parameters will be highlighted. 1. Up to 100 μm wide rectangular channels 2. Bosses and leak-free connections to external μ fluidics. 3. Web-like structures for inlets/outlets>100 μm. 4. Implementation of conductivity electrodes 5. Good thermal dissipation properties of the thin walls 6. Control of the electro osmotic flow by a radial voltage

A novel approach to low-power hot-surface devices with decoupled electrical and thermal resistances

This work employs the idea of maintaining a hot surface by means of dissipating power at a nano-scale conductive link. The link is created between two polysilicon electrodes separated by a dielectric (a capacitor-like structure). From modelling, a link of 10 nm in diameter should be possible to maintain the surface temperature ranging between 750 and 1150 K within the surface diameter of 2 μm by absorbing a 3.3 mW of electric power. The devices can also be designed in such a way that the hot surface area is reduced to a sub-μm-size hotspot. The main advantage of the proposed idea is decoupling the electrical resistance and thermal resistance of the device. In this paper, two device structures based on antifuse technology are described. Both the thermo-electrical properties and feasibility to perform as a Pellistor-type gas sensor are discussed

Deep drawing simulations of Tailored Blanks and experimental verification

Tailored Blanks are increasingly used in the automotive industry.\ud A combination of different materials, thickness, and coatings can be welded\ud together to form a blank for stamping car body panels. The main advantage\ud of using Tailored Blanks is to have specific characteristics at particular parts\ud of the blank in order to reduce the material weight and costs.\ud To investigate the behaviour of Tailored Blanks during deep drawing, the\ud finite element code DiekA is used. In this paper, simulations of the deep\ud drawing of two products using Tailored Blanks are discussed. For\ud verification, the two products are stamped to gain experimental information.\ud The correlation between the experimental results and the simulation results\ud appears to be satisfactory

Die konkrete eksperiment, die abstrakte begrip en die steeds ontvlugtende misterie van die natuurwetenskap.

Laat ons uitgaan van die empiries-induktiewe standpunt van dienatuurwetenskappe en nagaan hoe natuurwetenskaplike teorieë opgebouword. Wanneer ons dan van die konkrete eksperiment na die abstraktebegrip oorgaan, toon ’n ontleding aan dat die navorser, wat eers sekerwas, onseker word, en dat die pogings om tot ’n fundamentele teorie te kom teleurstel juis as gevolg van sy eensydige uitgangspunt

Vrye Radikale

Vrye radikale is hoogs aktiewe brokstukke van molekules, wat vir ’n breukdeel van ’n sekonde bestaan. Hulle neem deel aan ’n groot aantal chemiese reaksies, waaronder die vlam van ’nvuurhoutjie, ontploffings, elektriese ontladings, die absorpsie van suurstof deur word bemoeilik deur hulle hoë reaktiwitéit en die klein konsentrasies waarin hulle optree

'n Hoofstuk in die (outo)biografie van die predikant (pastor?)

This article makes a further contribution (chapter) to the existing debate (book) about the office, personality and spirituality of the pastor. Voices from literature, those of various pastors (biographical) and that of the author (autobiographical) direct the process of Participatory Action Research and supply the text. From various stories it becomes clear that the pastor is under pressure. Until now research was aimed on the one hand at indicating why pastors are under pressure and on the other hand how the causes can be managed. The sub-text speaks for the approach in this article when it is indicated that the acknowledgement of pain does not only give new meaning to the self, but to the pastoral duty as well. The development of the metaphor “wounded healer” and the associative networks it awakens, are important in the establishment of these accents in a new life text. This perspective ought to be articulated in the further development of metaphors for the description of the identity of the pastor

The Canonical Perfect Bose Gas in Casimir Boxes

We study the problem of Bose-Einstein condensation in the perfect Bose gas in the canonical ensemble, in anisotropically dilated rectangular parallelpipeds (Casimir boxes). We prove that in the canonical ensemble for these anisotropic boxes there is the same type of generalized Bose-Einstein condensation as in the grand-canonical ensemble for the equivalent geometry. However the amount of condensate in the individual states is different in some cases and so are the fluctuations.Comment: 23 page