Investigar en Trabajo Social: diferentes experiencias como pasantes de investigación

El presente trabajo se propone compartir tres experiencias de investigación llevadas a cabo por estudiantes (ahora licenciadas) en la Facultad de Trabajo Social de la Universidad Nacional de La Plata, en diferentes proyectos de investigación. Dos de las experiencias de pasantías se enmarcaron en el proyecto de investigación “Seguridad, Violencia y Derechos Humanos. Un estudio de las representaciones sociales en jóvenes y policías”1. La otra pasantía se inserta en el proyecto “Disputas en el espacio público: cultura, política y desigualdades socio-urbanas”2. A su vez, dos de nosotras continuamos nuestro proceso de aprendizaje del oficio de investigar a través de dos becas CIN en el marco de los proyectos de investigación acreditados, mencionados anteriormente. Haremos una breve mención respecto a esto. Por último, analizaremos las experiencias como pasantes de investigación a la luz de los aportes de distintos autores/as, haciendo hincapié principalmente en la comprensión de las competencias, habilidades y destrezas necesarias para desarrollar la práctica investigativa.Eje Teórico-metodológico en Trabajo Social-GT 27: Metodología y Trabajo Social.Facultad de Trabajo Socia

Elasticity in Bubble Rupture

When a Newtonian bubble ruptures, the film retraction dynamics is controlled by the interplay of surface, inertial, and viscous forces. In case a viscoelastic liquid is considered, the scenario is enriched by the appearance of a new significant contribution, namely, the elastic force. In this paper, we investigate experimentally the retraction of viscoelastic bubbles inflated at different blowing rates, showing that the amount of elastic energy stored by the liquid film enclosing the bubble depends on the inflation history and in turn affects the velocity of film retraction when the bubble is punctured. Several viscoelastic liquids are considered. We also perform direct numerical simulations to support the experimental findings. Finally, we develop a simple heuristic model able to interpret the physical mechanism underlying the process

Elasticity in Bubble Rupture

When a Newtonian bubble ruptures, the film retraction dynamics is controlled by the interplay of surface, inertial, and viscous forces. In case a viscoelastic liquid is considered, the scenario is enriched by the appearance of a new significant contribution, namely, the elastic force. In this paper, we investigate experimentally the retraction of viscoelastic bubbles inflated at different blowing rates, showing that the amount of elastic energy stored by the liquid film enclosing the bubble depends on the inflation history and in turn affects the velocity of film retraction when the bubble is punctured. Several viscoelastic liquids are considered. We also perform direct numerical simulations to support the experimental findings. Finally, we develop a simple heuristic model able to interpret the physical mechanism underlying the process

Elasticity in Bubble Rupture

When a Newtonian bubble ruptures, the film retraction dynamics is controlled by the interplay of surface, inertial, and viscous forces. In case a viscoelastic liquid is considered, the scenario is enriched by the appearance of a new significant contribution, namely, the elastic force. In this paper, we investigate experimentally the retraction of viscoelastic bubbles inflated at different blowing rates, showing that the amount of elastic energy stored by the liquid film enclosing the bubble depends on the inflation history and in turn affects the velocity of film retraction when the bubble is punctured. Several viscoelastic liquids are considered. We also perform direct numerical simulations to support the experimental findings. Finally, we develop a simple heuristic model able to interpret the physical mechanism underlying the process

Two different prostate cancer cell lines attach and proliferate on zein foams.

<p>A portion of the porous surface of a wpTPZ foam as observed by confocal microscopy at 20X (A) before cell seeding, and (B) 22RV1 cells after seven days of growth. Prostate cancer cell lines cultured on wpTPZ attach, proliferate, and develop into tree-like structures on the edge of wpTPZ foams: (C) 22RV1 cells observed at the third day of culture (24X; stereoscopic microscope); (D) Du145 cells observed at the third day of culture (24X; stereoscopic microscope).</p

Maize-derived thermoplastic were produced by (A) thermo-extrusion in a twin conical screw mini extruder (Haake MiniLab, Thermo Scientific, USA) followed by thermopressing at 20 MPa for 4 min in a P300P press (Collin, Germany).

<p>(B) Slabs of these plastics were subjected to supercritical CO₂ foaming, which occurred in two stages: (C) diffusion and solubilization of CO₂ molecules within a solid material matrix at supercritical conditions, and (D) a sudden drop in pressure allows the formation of CO₂ bubbles within the material.</p

(A) Samples of maize-derived thermoplastics exposed to supercritical CO₂ foaming exhibited different fold increases in thickness (blue), surface area (yellow), and volume (red).

<p>Insets show photographic images of samples elaborated from TPS, TPZ, and TBM140 (B) before and (C,D) after exposure supercritical CO₂ foaming.</p

Processing conditions used to elaborate maize derived bioplastics later exposed to CO₂ supercritical foaming conditions.

<p><b>Plasticizers:</b> Peg400: polyethylene-glycol 400; uf: urea/formamide; sg: sorbitol and glycerol mixture (1.4:1 wt/wt).</p><p><b>Bioplastics:</b> TPZ: thermoplasticized zein; TPS: thermoplasticized starch; TPBMx: thermoplasticized blue maize (x is a suffix that indicate extrusion temperature); TPmBM: thermoplasticized chemically modified blue maize (as described in materials and methods); Mix[TPS_y+TPZ]^a: thermoplasticized Blends of TPS and TPZ (80:20 wt/wt). The y subindex indicates the plasticizer used to produce TPS. ^aBlends were produced using the close mode compounding described in materials and methods.</p><p>Processing conditions used to elaborate maize derived bioplastics later exposed to CO₂ supercritical foaming conditions.</p

Scanning electronic microscope (SEM) micrographs and pore size distributions of foams.

<p>Foams made from (A) starch slabs thermoplasticized at 135°C and 50 rpm using urea/formamide as a plasticizer (sample TPSuf); observed at 1500X, and (B) at 2000X magnification. Foams made from zein slabs thermoplasticized at 75°C and 50 rpm (sample TPZ); observed at (C) 1500X, and (D) 2000X magnification. (E) The cumulative distribution of pore sizes, as calculated by image analysis of SEM micrographs, is presented for TPSuf foams (blue line) and Z foams (yellow line). Pore sizes are expressed in terms of projected areas ([=] μm²). The frequency distribution of pore sizes calculated by image analysis of SEM micrographs is presented for (F) TPSuf foams, and (G) TPZ foams.</p

Schematic representation of the experimental treatments and materials derived from them:

<div><p>TPZ: thermoplasticized zein; TPS: thermoplasticized starch; TPBMx: thermoplasticized blue maize (x is a suffix that indicates extrusion temperature); TPmBM: thermoplasticized chemically modified blue maize (as described in materials and methods); Mix[TPS_y+TPZ]^a: thermoplasticized blends of TPS and TPZ (80:20 wt/wt).</p> <p>The y subindex indicates the plasticizer used to produce TPS. ^aBlends were produced using the close mode compounding described in materials and methods. Plasticizers used where sg (sorbitol-glycerol); uf (urea-formamide); and PEG400 (poly-ethylene glycol with m.w. = 400 Da).</p></div