Helical serrated finned-tubes are well established in many thermal systems. This paper presents the results of numerical calculations carried out for the performance improvement of these devices. The work is divided into three main investigations conducted for Reynolds numbers between Re = 600 and 2600. The first investigation shows the effect of the fin serration, where a comparison between performances of finned tubes with and without fin serration is presented. Another main investigation is conducted on the effect of fin twisting of the outermost part of the fin on the performance of the serrated finned-tubes. Here, twisting angles considered are between β = 0• and 25• .The third investigation deals with the effect of the number of fin segments per period.

This article completes a systematic strategy for formulation and optimization of thermotropic systems with fixed domains (TSFDs) for overheating protection purposes. Focus was on characterization of morphology and on revealing optimization potential. A comprehensive characterization of scattering domain size and shape was done applying optical microscopy and scanning electron microscopy. In general, scattering domains exhibited inappropriate size and/or shape for optimum overheating protection performance. Moreover, several TSFD displayed defects (vacuoles, voids) resulting from thermomechanical or physicochemical interaction of matrix material and thermotropic additive during manufacturing. Morphological features along with solar optical and thermorefractive properties allowed for establishment of structure-property relationships. Light-shielding efficiency of TSFD correlated well with scattering domain size and shape. The majority of TSFD showing defects exhibited an increase of solar hemispheric transmittance upon heating. Several strategies to overcome defect formation and to improve scattering morphology were suggested and proof of concept was shown partially, thus indicating a significant optimization potential of the established TSFD. V C 2013 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2014, 131, 39910.

[1] Compared to "dry" atmospheric eruption of magma or "dry" magma/rock contact, intensity and time scale of heat discharge from magma to the surroundings is strongly modified by an effective coolant: water or water-sediment mixes. In the case of subaqueous or subglacial eruptions magma-water contact must take place and can result in phreatomagmatic explosions. Even if no explosions occur, rapid cooling results in the formation of pyroclasts by thermal granulation. To study this process in detail, a short-term calorimeter was built for the direct measurement of the heatflux from a magmatic melt to a coolant. Volcanic rocks from recent eruptions in Iceland were remelted and used to produce jets of melt poured into a coolant-filled container. Particles could be produced in a non-explosive process, that are practical identical to those from natural hyaloclastites. The process' fragmentation energy is about 10% of the total heat transferred from melt to coolant. Citation: Schmid, A.,

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