Het hoofd boven water : omgaan met beleving in het waterbeheer

Steeds vaker worden burgers actief betrokken bij het waterbeheer. Toch is participatie niet per definitie een garantie voor succes. Het slagen van burgerparticipatie hangt onder andere samen met het gestelde doel, het vinden van de juiste vorm en de mogelijkheid om het doel aan te laten sluiten bij bredere vormen van gebiedsontwikkeling. Alterra maakte drie praktijkhandelingen voor participatie, belevingsonderzoek en communicatie in het waterbeheer. Dit deel gaat over de beleving van betrokkenen bij waterbeheer. De belangrijkste onderwerpen per hoofdstuk zijn: de huidige maatschappelijke context waarin de beleving van burgers steeds belangrijker wordt (Hl); kennis over beleving van water en landschap, en onderzoeksmethoden binnen WaterTekens (H2); belevingswerelden leren kennen om beter te communiceren met betrokkenen (H3); de standpunten van betrokkenen leren begrijpen (H4); de wensen van betrokkenen voor de toekomst leren kennen (H5); het voorkomen van weerstand door rekening te houden met beleving (H6); de meningen over veranderingen in het verleden leren kennen (H7); en handvatten en overwegingen voor waterbeheerders die willen omgaan met beleving (H8

Interaction of vortices in superconductors with kappa close to 2^(-1/2)

Using a perturbative approach to the infinitely degenerate Bogomolnyi vortex state for a superconductor with kappa = 2^(-1/2), T -> T_c, we calculate the interaction of vortices in a superconductor with kappa close to 2^(-1/2). We find, numerically and analytically, that depending on the material the interaction potential between the vortices varies with decreasing kappa from purely repulsive (as in a type-II superconductor) to purely attractive (as in a type-I superconductor) in two different ways: either vortices form a bound state and the distance between them changes gradually from infinity to zero, or this transition occurs in a discontinuous way as a result of a competition between minima at infinity and zero. We study the discontinuous transition between the vortex and Meissner states caused by the non-monotonous vortex interaction and calculate the corresponding magnetization jump.Comment: v1:original submit v2:changed formate of images (gave problems to some) v3:corrected fig v4v6 (was -v4v6) orthographic corrections (and U_lat/int) mismatch v4:more small orthographic corrections v5:converted to revtex4 and bibTex v6:Renamed images to submit to pr

Выбор метода холецистэктомии у работников угольной промышленности с патологией органов дыхания

Проанализированы показатели центральной гемодинамики, газового состава и кислотно−щелочного равновесия крови у работников угольной промышленности с заболеваниями органов дыхания и желчнокаменной болезнью в зависимости от метода холецистэктомии. Показано, что лапаротомия является более оправданным методом хирургического лечения у больных с наличием сопутствующих профессиональных заболеваний органов дыхания по сравнению с лапароскопией.Проаналізовано показники центральної гемодинаміки, газового складу й кислотно−лужної рівноваги крові у працівників вугільної промисловості із захворюваннями органів дихання й жовчнокам'яною хворобою залежно від методу холецистектомії. Показано, що лапаротомія є більш виправданим методом хірургічного лікування у хворих із наявністю супутніх професійних захворювань органів дихання порівняно з лапароскопією.The parameters of central hemodynamics, gas composition and acid−base balance of the blood were analyzed in workers of coal industry with respiratory diseases and cholelithiasis depending on the method of cholecystectomy. It is shown that laparotomy is a more reasonable method of surgical treatment in patients with accompanying professional disease of the respiratory organs when compared with laparoscopy

Surface states in nearly modulated systems

A Landau model is used to study the phase behavior of the surface layer for magnetic and cholesteric liquid crystal systems that are at or near a Lifshitz point marking the boundary between modulated and homogeneous bulk phases. The model incorporates surface and bulk fields and includes a term in the free energy proportional to the square of the second derivative of the order parameter in addition to the usual term involving the square of the first derivative. In the limit of vanishing bulk field, three distinct types of surface ordering are possible: a wetting layer, a non-wet layer having a small deviation from bulk order, and a different non-wet layer with a large deviation from bulk order which decays non-monotonically as distance from the wall increases. In particular the large deviation non-wet layer is a feature of systems at the Lifshitz point and also those having only homogeneous bulk phases.Comment: 6 pages, 7 figures, submitted to Phys. Rev.

A Technique for generating Feynman Diagrams

We present a simple technique that allows to generate Feynman diagrams for vector models with interactions of order $2n$ and similar models (Gross-Neveu, Thirring model), using a bootstrap equation that uses only the free field value of the energy as an input. The method allows to find the diagrams to, in principle, arbitrarily high order and applies to both energy and correlation functions. It automatically generates the correct symmetry factor (as a function of the number of components of the field) and the correct sign for any diagram in the case of fermion loops. We briefly discuss the possibility of treating QED as a Thirring model with non-local interaction.Comment: 19 pages, LateX, To be published in Z. f. Phys.

Preliminary Investigation of Certain Laminar-Flow Airfoils for Application at High Speeds and Reynolds Numbers

In order to extend the useful range of Reynolds numbers of airfoils designed to take advantage of the extensive laminar boundary layers possible in an air stream of low turbulence, tests were made of the NACA 2412-34 and 1412-34 sections in the NACA low-turbulence tunnel. Although the possible extent of the laminar boundary layer on these airfoils is not so great as for specially designed laminar-flow airfoils, it is greater than that for conventional airfoils, and is sufficiently extensive so that at Reynolds numbers above 11,000,000 the laminar region is expected to be limited by the permissible 'Reynolds number run' and not by laminar separation as is the case with conventional airfoils. Drag measurements by the wake-survey method and pressure-distribution measurements were made at several lift coefficients through a range of Reynolds numbers up to 11,400,000. The drag scale-effect curve for the NACA 1412-34 is extrapolated to a Reynolds number of 30,000,000 on the basis of theoretical calculations of the skin friction. Comparable skin-friction calculations were made for the NACA 23012. The results indicate that, for certain applications at moderate values of the Reynolds number, the NACA 1412-34 and 2412-34 airfoils offer some advantages over such conventional airfoils as the NACA 23012. The possibility of maintaining a more extensive laminar boundary layer on these airfoils should result in a small drag reduction, and the absence of pressure peaks allows higher speeds to be reached before the compressibility burble is encountered. At lower Reynold numbers, below about 10,000,000, these airfoils have higher drags than airfoils designed to operate with very extensive laminar boundary layers

Simulations of cubic-tetragonal ferroelastics

We study domain patterns in cubic-tetragonal ferroelastics by solving numerically equations of motion derived from a Landau model of the phase transition, including dissipative stresses. Our system sizes, of up to 256^3 points, are large enough to reveal many structures observed experimentally. Most patterns found at late stages in the relaxation are multiply banded; all three tetragonal variants appear, but inequivalently. Two of the variants form broad primary bands; the third intrudes into the others to form narrow secondary bands with the hosts. On colliding with walls between the primary variants, the third either terminates or forms a chevron. The multipy banded patterns, with the two domain sizes, the chevrons and the terminations, are seen in the microscopy of zirconia and other cubic-tetragonal ferroelastics. We examine also transient structures obtained much earlier in the relaxation; these show the above features and others also observed in experiment.Comment: 7 pages, 6 colour figures not embedded in text. Major revisions in conten

Lockin to Weak Ferromagnetism in TbNi2B2C and ErNi2B2C

This article describes a model in which ferromagnetism necessarily accompanies a spin-density-wave lockin transition in the borocarbide structure provided the commensurate phase wave vector satisfies Q = (m/n)a* with m even and n odd. The results account for the magnetic properties of TbNi2B2C, and are also possibly relevant also for those of ErNi2B2C.Comment: 4 page

Waterbeelden : een studie naar de beelden van waternatuur onder medewerkers van Rijkswaterstaat

Het onderzoek bestaat uit vier delen: een schets van beelden van water in de Nederlandse cultuur en mogelijke veranderingen daarin; een literatuurstudie, uitmondend in een synthese, naar kennis over natuurbeelden, waar waternatuurbeelden afgeleiden van zijn; een inhoudsanalyse van documenten van Rijkswaterstaat, waarin uiteenlopende beelden van waternatuur bleken te overheersen; een gestructureerde vragenlijst onder medewerkers van Rijkswaterstaat. De gevonden waternatuurbeelden zijn het wilde, spontane, ruime, beonvloede en menselijke beeld