In contrast to earlier studies (Bothwell et al. 1993, 1994; DeNicola and Hoagland 1996; Kiffney et al. 1997b), Hill et al. (1997) recently concluded that there was no effect of ambient solar ultraviolet (UV) radiation on periphyton and grazers in a small Tennessee stream. These conclusions were based on the appearance that grazing pressure by pleurocerid snails (Elimia clavaeformis) controlled ...

Acrylic sheet, also known by the commercial names Plexiglas or Perspex, consists of poly(methyl methacrylate) (PMMA). Attractive to artists since its development in 1930s, it became especially popular during 1960s. In Portugal, knowledge about use and condition is scarce. this work, main Portuguese art collections were surveyed with goal gaining an overview acrylic sheet context current conditi...

Thermosense XXVI, vol. 5405, and is made available as an electronic reprint with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are p...

− Lock-in and pulse phase infrared thermography measurement techniques have been exploited for quantitative assessment of subsurface defects in a reference specimen made of Plexiglas. Radiometric thermal images were post-processed using a contrast approach in the frequency domain, allowing defect depth location to be resolved with a relative combined standard uncertainty of about 7% for thickne...

We study experimentally the propagation of an in-plane fracture into a transparent and heterogeneous Plexiglas block. A stable crack propagation in mode I is monitored by an imposed displacement. The experimental setup allows a high resolution observation of the crack front in situ. Self-affine properties of the crack front are described over more than three decades using several techniques: va...

We report on the development of transducers for ultrasonic flaw detection which can be permanently mounted at critical locations on structures. We will show that MEMS capacitive diaphragm transducers can be bonded to metal or plexiglas test speciments without damage and that ultrasonic energy can be efficiently coupled into the transducer. It will be demonstrated that transducer arrays can be o...

We present an experimental study of the displacement of a light intruder immersed in a vibrated granular bed. Using high speed video we resolve the motion, during one cycle of oscillation, of a cylindrical object inside a Plexiglas box partially filled with grains. We report experimental evidence that, in the absence of convection, at least two forces are behind the intruder's motion: an air dr...

The problem of transient natural convection in a cube-shaped cavity is investigated experimentally and numerically. The motion is driven by a sudden temperature difference applied to two opposite side walls of the vessel. The experiments are performed at a Rayleigh number of 1.66 · 10 and a Prandtl number of 1109, inside a 5 · 5 · 5cm cavity made of plexiglas, with two isothermal copper walls k...

The portable anteroposterior (AP) radiograph (CXR) is an essential component of clinical management in the intensive care unit (ICU). In view of the immobility of patients, and overlying tubes, wires, and catheters, lateral (LAT) CXRs are infrequently ordered. We constructed a portable acrylic (Plexiglas) CXR cassette holder and were able to obtain reproducible quality LAT CXRs in the ICU. Of t...

Polar indole-3-acetic acid movement was observed in killed plant segments and in artificial model systems. The polar diffusion of indole-3-acetic acid was observed in tissue killed by chemical or physical means in an agar-plant system and in a multicelled Plexiglas dialysis chamber containing hypocotyl tissue gradients or gradients of anion exchange material.It was suggested that polar indole-3...