Papers by Keyword: Porous Layers

Abstract: This work experimentally explored the free convection heat transfer characteristics of finned heat sink with sintered-metal-beads layers. It has been proven that the metallic porous media can enhance the forced convection heat transfer efficiently. This work sintered the metal beads to adhere onto the both side surfaces of each radial plate fin of the metallic heat sink, and investigated whether the sintered-metal-beads layers promote the free convection heat transfer or not. The 0.5~0.85mm-diameetr bronze beads were employed. They were sintered smooth with the radial plate fins of the copper heat sink by thin layers at high temperature. The experimental groups were the plate-shape sintered-metal-beads and strip-shape sintered-metal-beads heat sinks. The pure copper finned heat sink was set as the control group. The results demonstrated that the thermal resistances of the experimental groups were separately 20.7% and 11.6% higher than that of the control group at the smaller temperature difference between the heated surface and the ambient (△T≈30°C); while the thermal resistances of the experimental groups were separately 15.3% and 6.9% higher than that of the control group at △T≈60°C. In general, the present sintered-metal-beads layers cannot strengthen the free convection heat transfer.

Abstract: Real-time, on-body measurement using minimally invasive biosensors opens up new perspectives for diagnosis and disease monitoring. Wearable sensors are placed in close contact with the body, performing analyses in accessible biological fluids (wound exudates, sweat). In this context, a network of biosensing optical fibers woven in textile enables the fabric to measure biological parameters in the surrounding medium. Optical fibers are attractive in view of their flexibility and easy integration for on-body monitoring. Biosensing fibers are obtained by modifying standard optical fibers with a sensitive layer specific to biomarkers. Detection is based on light absorption of the sensing fiber, placing a light source and a detector at both extremities of the fiber. Biosensing optical fibers have been developed for the in situ monitoring of wound healing, measuring pH and the activity of proteases in exudates. Other developments aim at the design of sensing patches based on functionalized, porous sol-gel layers, which can be deposited onto textiles and show optical changes in response to biomarkers. Biosensing textiles present interesting perspectives for innovative healthcare monitoring. Wearable sensors will provide access to new information from the body in real time, to support diagnosis and therapy.

Abstract: Kinetics of porous layer evolution during high-temperature annealing was investigated by Monte Carlo simulation. Sintering process of spongy one-component films with randomly distributed pores was studied. Layers with porosity from 20% to 50% with simple cubic and diamond-like lattices were under examination. Sintering rate was demonstrated to be non-monotone in time for any film porosity and different lattice coordination number. Metastable states of the system, dependent on time and temperature of annealing process, were revealed. Estimation of annealing time necessary to reach the definite sintering level under changes of annealing temperature was suggested.