Minimalisme (art) | EPFL Graph Search

Le minimalisme (ou art minimal) est un mouvement de l'art contemporain, apparu au début des années 1960 aux États-Unis, en réaction au lyrisme pictural de l'expressionnisme abstrait et en opposition à la tendance figurative et ironique du pop art. Le minimalisme est l'héritier du modernisme, et plus particulièrement du Bauhaus. Il fait sienne la maxime d'un des grands représentants du Bauhaus, Ludwig Mies van der Rohe : « less is more », l'amélioration d'une œuvre se faisant selon les minimalistes par soustraction. Parmi les grands représentants du minimalisme, on trouve les sculpteurs Robert Morris, Carl Andre et Donald Judd, les peintres Frank Stella et Sol Le Witt, les musiciens La Monte Young, Terry Riley, Philip Glass et Steve Reich. Ces artistes ont en commun de privilégier le dépouillement formel, le réductionnisme et la neutralité. La définition de la notion d’« art minimal » a été donnée à la fin de l'année 1965 par le philosophe analytique anglais Richard Wollheim dans Ar

Weakening effect of various pore fluids on the tensile strength of granite

Guanyi Lu

Laboratory three-point bending experiments are carried out to evaluate the effect of various fluids on the tensile strength of granite. The granite specimens were tested under both dry and saturated conditions. The fluids used to saturate the granite include distilled water, hydrochloric acid (HCl), sodium hydroxide (NaOH), kerosene, and hydraulic oil. The experimental results indicate the strength of granite is decreased when saturated by fluids compared to its value measured from dry samples. Compared to the dry granite specimens, water, HCl, NaOH, kerosene, and hydraulic oil reduce the tensile strength of granite by 26, 37, 28, 23, and 41%, respectively. The test data indicates that non-aqueous solution does not have noticeably different effect on reduction of the tensile strength compared to the aqueous solution. However, fluid viscosity is found to have profound impact on the results as a more viscous non-aqueous solution, hydraulic oil, greatly lowers the strength compared with those specimens saturated with less viscous kerosene. The experiments suggest that chemical fluid-rock interaction plays a minimal role in such constant loading rate tests that the failure occurs rapidly. On the other hand, the mechanical influence of the fluid, such as lubrication of grain boundaries and/or local pore pressure generation might play an important role in the determination of the strength of granite.

SPRINGER HEIDELBERG2022

Optimization of the Distance between Cylindrical Light Distributors Used for Interstitial Light Delivery in Biological Tissues

Aurelien Stephen Arnaud Gregor, Georges Wagnières

Cylindrical light diffusers (CLDs) are often employed for the treatment of large tumors by interstitial photodynamic therapy (iPDT) and photoimmunotherapy (PIT), which involves careful treatment planning to maximize therapeutic dose coverage while minimizing the number of CLDs used. There is, however, a lack of general guidelines regarding optimal positioning of CLDs, in particular when they are inserted in parallel to treat head and neck squamous cell cancer (HNSCC). Therefore, the purpose of this study is to determine the CLD-CLD distances maximizing the necrosis for different geometries of CLD positions and shed light on the influence of different optical parameters on this distance, in particular when HNSCCs are treated by interstitial PIT with cetuximab-IR700 using up to seven CLDs. To that end, Monte-Carlo simulations of the light propagation around CLDs inserted perpendicularly in a semi-infinite tumor were performed to determine the volume receiving a fluence larger than a therapeutic threshold. An optimization algorithm was then used to calculate and maximize the necrosed tumor volumes. Tumor optical properties were derived from published data. Our findings suggest that optimal CLD positioning maximizing the volume of necrosed tumor during interstitial PIT for typical HNSCC optical properties corresponds to a CLD-CLD distance between 11.5- and 13-mm. Variations of the absorption and reduced scattering coefficients have the greatest influence on CLD placements, while tissue anisotropy factor, CLD insertion geometry, CLD length, and the angular dependence of the radiance emitted by the CLDs have minimal influence. At first approximation the influence of these optical parameters on optimal CLD-CLD distance are independent. Our data also suggests it is possible to derive new treatment plans using knowledge of previous treatment plans.

MDPI2022

Optimization of the Distance between Cylindrical Light Distributors Used for Interstitial Light Delivery in Biological Tissues

Aurelien Stephen Arnaud Gregor, Georges Wagnières

MDPI2022