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[en] A two-dimensional transient thermal model of an injection laser is developed. This model makes it possible to analyse the temperature profiles in pulsed and cw stripe lasers with an arbitrary width of the stripe contact, and also in linear laser-diode arrays. This can be done for any durations and repetition rates of the pump pulses. The model can also be applied to two-dimensional laser-diode arrays operating quasicontinuously. An analysis is reported of the influence of various structural parameters of a diode array on the thermal regime of a single laser. The temperature distributions along the cavity axis are investigated for different variants of mounting a crystal on a heat sink. It is found that the temperature drop along the cavity length in cw and quasi-cw laser diodes may exceed 20%. (lasers)

[en] This paper summarizes different kinds of heat sinks on the market for high power LED lamps. Analysis is made on the thermal model of LED, PCB and heat sink separately with a simplified mode provided. Two examples of simulation are illustrated as a demonstration for the thermal simulation as guidance for LED lamp design. (semiconductor devices)

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[en] A micro-channel is a common component in various fields, for example, micro-channel heat sink, compact heat exchanger, and lap-on-a-chip. In this study, we investigated the effects of surfactant on the bubble motion of nitrogen gas in a 510 μm x 470 μm rectangular micro-channel using a sodium dedecyl sulfate (SDS) surfactant. We selected different concentrations of SDS based on the surface tension of water (70 mN/m). The mole fraction of 1.9 mM and 3.71 mM show a surface tension of 60.29 mN/m and 50.62 mN/m, respectively. These will be expressed as Water 70, SDS 60 and SDS 50. More details including experimental facilities and procedure were described in Choi et al.'s previous work

[en] After Fukushima: complements to the harmonization of safety practices for GEN-IV reactors: • Hazards would be a major challenge for GEN-IV reactor designs. • They should be comprehensively addressed accounting for the outcomes of post-Fukushima investigations, also including the European stress tests. • Investigation on specific GEN IV issues (identified by SARGEN IV) should include: - The total loss of power sources; - The total loss of the ultimate heat sink(s); - The combination of both losses; - The management of a severe accident engendered by these losses; - Provisions allotted to improve the grace period before cliff-edge effects; Hardened equipments

[en] High duty cycle operation of quantum cascade superlattice lasers with graded superlattice active regions is investigated with the goal of achieving high average optical power. The optical output power increases with pulse width and decreases with heat sink temperature. This behavior is explained on the basis of the laser core temperature oscillations during the pulsed, high duty cycle operation. Between 175 and 325 K heat sink temperature, optimum duty cycles vary from 10% to 1% and average power levels vary from 50 to 1 mW for various lasers used in this study. [copyright] 2001 American Institute of Physics

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[en] Due to an overall trend towards less heating and more cooling demands in buildings in many European countries over the last few decades, passive cooling by night-time ventilation is seen as a promising technique, particularly for commercial buildings in the moderate or cold climates of Central, Eastern and Northern Europe. The basic concept involves cooling the building structure overnight in order to provide a heat sink that is available during the occupancy period. In this study, the potential for passive cooling of buildings by night-time ventilation was evaluated by analysing climatic data, without considering any building-specific parameters. An approach for calculating degree-hours based on a variable building temperature - within a standardized range of thermal comfort - is presented and applied to climatic data of 259 stations all over Europe. The results show a high potential for night-time ventilative cooling over the whole of Northern Europe and still significant potential in Central, Eastern and even some regions of Southern Europe. However, due to the inherent stochastic properties of weather patterns, a series of warmer nights can occur at some locations, where passive cooling by night-time ventilation alone might not be sufficient to guarantee thermal comfort