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The collection, storage, and use of energy and information are important issues for overcoming the global energy shortage while satisfying the demand for information transmission. This research reports a nano-Fe 3 O 4 and erythritol (ER)-functionalized, cross-linked methyl cellulose aerogel (MC−EP) composite that has the characteristics of phase-change energy storage as the magnetic and ultraviolet responses requisite for light-to-heat conversion and storage. The nano-Fe 3 O 4 particles in MC−EP− ER-75 were fixed and filled into pore structures in MC−EP. ER was used to form an effective combination with MC−EP. The addition of nano-Fe 3 O 4 compensated for the low thermal conductivity of ER. The MC−EP−ER-75 was able to store solar radiationinduced energy due to the loading of ER at a photothermal conversion efficiency of 79.67% and a light-to-heat conversion efficiency of 79.67%. The results of thermal stability (TGA) analysis showed that MC−EP−ER-75 was thermally degraded acceptably below 200 °C. The differential scanning calorimetry curve and latent heat values (melting/crystallization enthalpies of 314.8 and 197.9 J/g, respectively) of MC−EP−ER-75 did not change after 100 cycles. In addition, it exhibited excellent saturation magnetization, superparamagnetism, and ultraviolet shielding, as well as a rapid response to the ultraviolet and magnetic fields. This provided a way to prepare light-to-heat conversion−storage−release materials and ultraviolet−magnetic sensors that can be used in renewable resources.

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This study numerically investigates the limitations of structural hot-spot stress (SHSS) methods and proposes a guideline for the calculation of hot-spot stresses, which can be used for the better evaluation of fatigue-related problems. Four different SHSS evaluation methods have been applied to the rib-to-deck (RD) welded joint in orthotropic steel deck (OSD). These methods are used to calculate SHSS at this critical joint utilizing finite element analyses (FEA) based software Siemens NX.12. The limitations and the accuracy of these methods have been observed under different element types and meshing techniques. Moreover, the effect of the nodal-averaging feature is being studied. Two types of governing stresses are produced by the application of Eurocode fatigue load model-4. Essentially, the bending in deck-plate produces highly non-linear stress at the deck-toe, and the membrane effect in rib-plate generates linear stress at the rib-toe. Guidelines are proposed considering different parameters on these two stress states by applying SHSS evaluation methods. In comparison to other SHSS approaches, the International Institute of Welding (IIW) quadratic stress extrapolation (QSE) method shows better results for solid single-element, and the American Society of Mechanical Engineers (ASME) through thickness stress linearization (TTSL) method stands out in solid cubic-mesh technique. In general, shell elements have more consistent SHSS results as compared to solid elements for both stress states.

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