Archivos abiertos : Sonido, imagen y cosa en obras de Christian Boltanski, Oscar Muñoz y Grete Stern

El archivo tiene un estatus complejo y ambivalente. Puede ser un instrumento al servicio del poder y también ser albergue de conocimiento potencialmente emancipador capaz de desestabilizar verdades establecidas. Este trabajo propone recorrer e interrogar los usos que algunas intervenciones del arte moderno y contemporáneo realizaron con el soporte archivo, pensado antes que como repositorio inmóvil de saberes, discursos y conocimientos, como una norma que regula un tráfico de bienes simbólicos. Mi lectura intentará reconocer al archivo como un soporte contingente, mutante y dinámico, y recorrer algunos de los usos que el arte moderno y contemporáneo, en particular la fotografía y algunas zonas adyacentes han realizado con él

Archivos abiertos : Sonido, imagen y cosa en obras de Christian Boltanski, Oscar Muñoz y Grete Stern

El archivo tiene un estatus complejo y ambivalente. Puede ser un instrumento al servicio del poder y también ser albergue de conocimiento potencialmente emancipador capaz de desestabilizar verdades establecidas. Este trabajo propone recorrer e interrogar los usos que algunas intervenciones del arte moderno y contemporáneo realizaron con el soporte archivo, pensado antes que como repositorio inmóvil de saberes, discursos y conocimientos, como una norma que regula un tráfico de bienes simbólicos. Mi lectura intentará reconocer al archivo como un soporte contingente, mutante y dinámico, y recorrer algunos de los usos que el arte moderno y contemporáneo, en particular la fotografía y algunas zonas adyacentes han realizado con él

Archivos abiertos : Sonido, imagen y cosa en obras de Christian Boltanski, Oscar Muñoz y Grete Stern

El archivo tiene un estatus complejo y ambivalente. Puede ser un instrumento al servicio del poder y también ser albergue de conocimiento potencialmente emancipador capaz de desestabilizar verdades establecidas. Este trabajo propone recorrer e interrogar los usos que algunas intervenciones del arte moderno y contemporáneo realizaron con el soporte archivo, pensado antes que como repositorio inmóvil de saberes, discursos y conocimientos, como una norma que regula un tráfico de bienes simbólicos. Mi lectura intentará reconocer al archivo como un soporte contingente, mutante y dinámico, y recorrer algunos de los usos que el arte moderno y contemporáneo, en particular la fotografía y algunas zonas adyacentes han realizado con él

Difusión y consumo de la fotografía etnográfica chaqueña. En: Avá, nº 16

El trabajo reflexiona sobre la experiencia de difusión y consumo de dos colecciones fotográficas del siglo XX: la primera reúne las imágenes tomadas por Grete Stern entre 1958-1964 a pueblos originarios del Gran Chaco y la segunda, las fotos obtenidas por Pedro Luis Raota cerca de 1978 en las colonias inmigrantes de Resistencia y localidades aledañas. Ambas colecciones atraviesan procesos disímiles de circulación y exhiben desde ópticas e intereses diferentes, realidades contrapuestas del Chaco. Por ello, el trabajo explora algunos de los contextos subjetivos y colectivos en los que ambas colecciones fueron utilizadas respectivamente como herramienta de investigación académica y material de exhibición estética. Se analiza especialmente la apropiación de estas imágenes por parte del sector hegemónico y se discute en qué medida las colecciones pertenecen a los sujetos representados y/o sus descendientes y por lo tanto deben ser “devueltas” a ellos.

Bow and stern flows with constant vorticity

Free surface flows of a rotational fluid past a two-dimensional semi-infinite body are considered. The fluid is assumed to be inviscid, incompressible, and of finite depth. A boundary integral method is used to solve the problem for the case where the free surface meets the body at a stagnation point. Supercritical solutions which satisfy the radiation condition are found for various values of the Froude number and the dimensionless vorticity. Subcritical solutions are also found; however these solutions violate the radiation condition and are characterized by a train of waves upstream. It is shown numerically that the amplitude of these waves increases as each of the Froude number, vorticity and height of the body above the bottom increases.

Linear stern waves in finite depth channels

This paper formulates an analytically tractable problem for the wake generated by a long flat bottom ship by considering the steady free surface flow of an inviscid, incompressible fluid emerging from beneath a semi-infinite rigid plate. The flow is considered to be irrotational and two-dimensional so that classical potential flow methods can be exploited. In addition, it is assumed that the draft of the plate is small compared to the depth of the channel. The linearised problem is solved exactly using a Fourier transform and the Wiener-Hopf technique, and it is shown that there is a family of subcritical solutions characterised by a train of sinusoidal waves on the downstream free surface. The amplitude of these waves decreases as the Froude number increases. Supercritical solutions are also obtained, but, in general, these have infinite vertical velocities at the trailing edge of the plate. Consideration of further terms in the expansions suggests a way of canceling the singularity for certain values of the Froude number.

Minimising wave drag for free surface flow past a two-dimensional stern

Free surface flow past a two-dimensional semi-infinite curved plate is considered, with emphasis given to solving for the shape of the resulting wave train that appears downstream on the surface of the fluid. This flow configuration can be interpreted as applying near the stern of a wide blunt ship. For steady flow in a fluid of finite depth, we apply the Wiener-Hopf technique to solve a linearised problem, valid for small perturbations of the uniform stream. Weakly nonlinear results found using a forced KdV equation are also presented, as are numerical solutions to the fully nonlinear problem, computed using a conformal mapping and a boundary integral technique. By considering different families of shapes for the semi-infinite plate, it is shown how the amplitude of the waves can be minimised. For plates that increase in height as a function of the direction of flow, reach a local maximum, and then point slightly downwards at the point at which the free surface detaches, it appears the downstream wavetrain can be eliminated entirely.

Two-dimensional bow and stern flows in a finite-depth fluid with constant vorticity

This thesis is concerned with two-dimensional free surface flows past semi-infinite surface-piercing bodies in a fluid of finite-depth. Throughout the study, it is assumed that the fluid in question is incompressible, and that the effects of viscosity and surface tension are negligible. The problems considered are physically important, since they can be used to model the flow of water near the bow or stern of a wide, blunt ship. Alternatively, the solutions can be interpreted as describing the flow into, or out of, a horizontal slot. In the past, all research conducted on this topic has been dedicated to the situation where the flow is irrotational. The results from such studies are extended here, by allowing the fluid to have constant vorticity throughout the flow domain. In addition, new results for irrotational flow are also presented. When studying the flow of a fluid past a surface-piercing body, it is important to stipulate in advance the nature of the free surface as it intersects the body. Three different possibilities are considered in this thesis. In the first of these possibilities, it is assumed that the free surface rises up and meets the body at a stagnation point. For this configuration, the nonlinear problem is solved numerically with the use of a boundary integral method in the physical plane. Here the semi-infinite body is assumed to be rectangular in shape, with a rounded corner. Supercritical solutions which satisfy the radiation condition are found for various values of the Froude number and the dimensionless vorticity. Subcritical solutions are also found; however these solutions violate the radiation condition and are characterised by a train of waves upstream. In the limit that the height of the body above the horizontal bottom vanishes, the flow approaches that due to a submerged line sink in a $90^\circ$ corner. This limiting problem is also examined as a special case. The second configuration considered in this thesis involves the free surface attaching smoothly to the front face of the rectangular shaped body. For this configuration, nonlinear solutions are computed using a similar numerical scheme to that used in the stagnant attachment case. It is found that these solution exist for all supercritical Froude numbers. The related problem of the cusp-like flow due to a submerged sink in a corner is also considered. Finally, the flow of a fluid emerging from beneath a semi-infinite flat plate is examined. Here the free surface is assumed to detach from the trailing edge of the plate horizontally. A linear problem is formulated under the assumption that the elevation of the plate is close to the undisturbed free surface level. This problem is solved exactly using the Wiener-Hopf technique, and subcritical solutions are found which are characterised by a train of sinusoidal waves in the far field. The nonlinear problem is also considered. Exact relations between certain parameters for supercritical flow are derived using conservation of mass and momentum arguments, and these are confirmed numerically. Nonlinear subcritical solutions are computed, and the results are compared to those predicted by the linear theory.

Judge Max Frankenbach of Berlin hiking with his wife Grete Frankenbach nee Bernstein; Sassal-Massone Portraits Couples

Digital Image

Paula Wallerstein nee Molling holding her grandson Hans Stern.

Digital Image

Lotte Stern and Dr. Alfred Stern with Otto Wallerstein, a relative of Lotte's father; Berkeley, California.

From left to right: Lotte Stern, Otto Wallerstein, Alfred Stern; Photograph taken shortly after arrival in Berkeley, California

Fritz Gottschalk, Therese Gottschalk nee Molling and Lotte Stern nee Wallerstein on a hiking tour in the mountains.

Therese Gottschalk nee Molling, wife of Fritz Gottschalk; Lotte Stern nee Wallerstein, 1st cousin of Lotte Stern nee Wallerstein

Therese Mayerhof nee Molling with Joel, Ilse, Adolf, Grete, and Leopold Meyerhof on rooftop of store and residence Meyerhof am Platze; Hildesheim, Germany.

From left to right, standing: Ilse, Adolf, Grete and Lepold Meyerhof; from left to right, sitting: Joel Meyerhof and Therese Mayerhof nee Molling

Portrait of Joseph Rothschild and his wife Rosalie nee Stern; Bad Ems, Germany. Portraits Couples

Handwritten on verso of original photograph: Joseph u Rosalie Rothschild

Studio portrait of Liselotte "Lotte" Stern nee Wallerstein.

Photograph probably taken shortly before her marriage to Alfred Stern in 1928.