FRANCESCA WOODMAN: WATER SPECIFIED

Paul de Man makes a distinction between interpretation and reading as that which finds meaning in a text versus an analysis of the relationship between a text’s rhetorical and grammatical dimensions, respectively. Interpretation, as he defines it, assumes that a text’s meaning is largely transparent and that there is no disharmony between how it means and what it means. Reading, on the other hand, makes no such assumptions: it shows how a text’s meaning cannot be reduced to grammar and seeks out moments of indeterminacy between its literal and figurative meanings. I propose a “reading” of Francesca Woodman’s photographs that demonstrates how the critical, largely feminist, literature on the artist engages in interpretation and thus fails to appreciate the artist’s exploration of photography’s conditions of representation. In the process, I argue that her photographs function like hypograms, a concept of de Man by way of Saussure, or infra-texts. In short, Woodman’s photographs are readings of photography and womanhood and her art defies conventional understandings of artistic identity and agency.     

Process parameter dependencies of continuous and pulsed laser modes on surface polishing of additive manufactured aluminium AlSi10Mg parts

Laser powder bed fusion is a well-established 3D printing technique for metal alloys, but exhibits a poor surface quality. Laser polishing provides the possibility of a fast contact-free and fully-automatable surface treatment. This paper deals with the experimental investigation of laser polishing of laser powder bed fusion parts made of aluminium AlSi10Mg. Laser polishing is done with a 4 kW solid state disc laser in combination with a multi-axis system and a one dimensional scanner optic. The laser is operated at continuous and pulsed operation mode. The parameter study reveals a high dependency of the achievable roughness on the laser beam intensity, the track and pulse overlap, the energy density and the number of polishing passes and polishing directions. Pulsed laser polishing mode with up to four passes from different directions revealed the lowest surface roughness of 0.14 μm Ra. With respect to the initial average surface roughness of Ra = 8.03 μm a reduction of the surface roughness of greater than 98 % could be achieved. Polishing with continuous laser radiation at one polishing pass resulted in Ra = 0.23 μm at an area rate of 20 cm²/min. Laser polishing using four passes achieved a further improvement up to Ra = 0.14 μm.     

Flash Sintering using Controlled Current Ramp

In conventional flash sintering, the current rises nonlinearly to a set current limit, accompanied by a spike in the power density. This sudden power spike may cause hot spot formation, in which current preferentially channels through a small area, causing localized melting while other areas remain unsintered. By using a controlled current ramp early on the sudden power spike can be avoided. In addition, by changing the ramp rate material properties such as porosity, grain size and conductivity can be tuned.     

Damage microstructure evolution of helium ion irradiated SiC under fusion relevant temperatures

In-situ transmission electron microscopy (TEM) with ion irradiation has been used to study the damage microstructure evolution of He ion irradiated 4-H SiC at nuclear fusion relevant temperatures. The SiC samples were irradiated with 20?keV He ions at 25, 400, 800 and 1200?°C to a dose of 5.0 displacements per atom (DPA). At 25?°C, the material fully amorphises at 1.5 DPA and no He bubble nucleation occurs up to the doses studied. At 400 and 800?°C, He bubble nucleation occurs and the material remains crystalline. Bubble nucleation occurs at 2.0?DPA at 400?°C but occurs at only 0.5?DPA at 1200?°C. This is attributed the He atoms de-trapping from vacancies and migrating interstitially to larger He-vacancy clusters at higher temperatures, leading to faster nucleation of observable He bubbles. Helium platelets form at an irradiation temperature of 1200?°C at 0.5?DPA showing a preference for nucleation between the {0001} basal planes.     

In this issue

Software Quality Journal -     

The Role of Cholesterol on Triterpenoid Saponin-Induced Endolysosomal Escape of a Saporin-Based Immunotoxin

Cholesterol seems to play a central role in the augmentation of saporin-based immunotoxin (IT) cytotoxicity by triterpenoid saponins. Endolysosomal escape has been proposed as one mechanism for the saponin-mediated enhancement of targeted toxins. We investigated the effects of lipid depletion followed by repletion on Saponinum album (SA)-induced endolysosomal escape of Alexa Fluor labelled saporin and the saporin-based immunotoxin OKT10-SAP, directed against CD38, in Daudi lymphoma cells. Lipid deprived cells showed reduced SA-induced endolysosomal escape at two concentrations of SA, as determined by a flow cytometric method. The repletion of membrane cholesterol by low density lipoprotein (LDL) restored SA-induced endolysosomal escape at a concentration of 5 µg/mL SA but not at 1 µg/mL SA. When LDL was used to restore the cholesterol levels in lipid deprived cells, the SA augmentation of OKT10-SAP cytotoxicity was partially restored at 1 µg/mL SA and fully restored at 5 µg/mL SA. These results suggest that different mechanisms of action might be involved for the two different concentrations of SA and that endosomal escape may not be the main mechanism for the augmentation of saporin IT cytotoxicity by SA at the sub-lytic concentration of 1 µg/mL SA.     

An Adaptable and Scalable Generator of Distributed Massive MIMO Baseband Processing Systems

Journal of Signal Processing Systems - This paper presents an algorithm-adaptable, scalable, and platform-portable generator for massive multiple-input multiple-output (MIMO) baseband processing...