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The thermal behavior of a poly(methylmethacrylate) (PMMA) pigmented with titanium dioxide (TiO2) is studied in both Steady state and transient regimes in the present work. The numerical results of thermal conductivity, based on the finite element method, are compared to theoretical models and experimental measurements, which varies depending on the quenching temperature and pigment content. Time evolution of temperatures during the quenching of the composite is taken into account for different quenching temperatures and different pigment contents. It is noted that the heat exchange becomes slower for a pigment fraction of 0.5%, and the steady state is reached more rapidly for higher pigment content. The AFM image of the PMMA/TiO2 composite with content equal to 3% of titanium dioxide. This demonstrates a good distribution of the particles throughout the matrix, with the individual particles being uniformly dispersed and securely embedded in the polymer matrix, thereby avoiding any clustering. An improvement in heat exchange is observed in the composite with a high content of titanium dioxide. This improvement is attributed to the increase in the thermal conductivity of the PMMA/TiO2 composite. [ABSTRACT FROM AUTHOR]

In this study, the effects of the free quenching temperature on mechanical, thermomechanical and thermophysical properties of pigmented polystyrene (PS/TiO2) with 3% of TiO2 were investigated. Thermal conductivity and thermal diffusivity of the titanium dioxide pigmented polystyrene were measured using a periodic method. The results show a slow improvement of the notched Izod impact strength obtained after a second quenching at 15 and 35°C; whereas thermal conductivity and diffusivity reached a minimum value at the quenching temperature of 35°C. However, the effect on the thermophysical properties is only noted for the second quenching temperature 35°C. The study allowed examining the effect of quenching temperature, filler concentration and material thickness on the transient thermal behavior of the titanium dioxide pigmented polystyrene. [ABSTRACT FROM AUTHOR]

The purpose of this work was to investigate the influence of thermal annealing and quenching on mechanical, and thermomechanical properties of acrylonitrile butadiene styrene (ABS). The free quenching was applied over a temperature range starting from a temperature slightly above Tg to temperatures below 0°C. The improvement of the impact strength is linked to the cavitation of the rubber particles close to the samples surface. The existence of a relaxation mode located around-10°C may participate to the relaxation of the residual stresses when the sample is quenched under 0°C, this phenomenon would promote cavitation. [ABSTRACT FROM AUTHOR]

Thermal properties of two composites prepared by using a polypropylene matrix filled with aluminum (slightly oxidized) and copper fillers were investigated. For each of these fillers two different particle sizes were used. We have shown an anomalous thermal behavior when these metallic fillers are slightly oxidized, i.e. higher thermal transport is obtained for PP/Al composites when using the largest particles. So, the PP/Al composites thermal behavior is not consistent with the PP/Cu ones and with the literature results reported for dielectric or conducting filler particles in a polymeric matrix. Thus, these PP/Al composites exhibit higher thermal transport properties than the homopolymer matrix where as electrical insulating properties of PP are preserved. This kind of composite structure might be of great interest in some technological applications where both good electrical insulation and high thermal conduction are required. [ABSTRACT FROM AUTHOR]

This article presents a study conducted to evaluate the monthly trend of Gasterophilosis through the survey of egg-laying by adult flies in different topographic regions of horses. Researchers conducted a survey on egg-laying by adults of Gasterophilus in four study farms from October 2005 to September 2006. Results revealed that adult flies demonstrate egg-laying activity during most part of the year.

Head-down tilt (HDT) has been widely proposed as a terrestrial analog of microgravity and used also to investigate the occurrence of spaceflight-associated neuro-ocular syndrome (SANS), which is currently considered one of the major health risks for human spaceflight. We propose here an in vivo validated numerical framework to simulate the acute ocular-cerebrovascular response to 6° HDT, to explore the etiology and pathophysiology of SANS. The model links cerebral and ocular posture-induced hemodynamics, simulating the response of the main cerebrovascular mechanisms, as well as the relationship between intracranial and intraocular pressure to HDT. Our results from short-term (10 min) 6° HDT show increased hemodynamic pulsatility in the proximal-to-distal/capillary-venous cerebral direction, a marked decrease (-43%) in ocular translaminar pressure, and an increase (+31%) in ocular perfusion pressure, suggesting a plausible explanation of the underlying mechanisms at the onset of ocular globe deformation and edema formation over longer time scales., (© 2024. The Author(s).)