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Thermal metamaterials and devices based on transformation thermodynamics often require materials with anisotropic and inhomogeneous thermal conductivities. In this study, still based on the concept of transformation thermodynamics, we designed a planar illusion thermal device, which can delocalize a heat source in the device such that the temperature profile outside the device appears to be produced by a virtual source at another position. This device can be constructed by only one kind of material with constant anisotropic thermal conductivity. The condition which should be satisfied by the device is provided, and the required anisotropic thermal conductivity is then deduced theoretically. This study may be useful for the designs of metamaterials or devices since materials with constant anisotropic parameters have great facility in fabrication. A prototype device has been fabricated based on a composite composed by two naturally occurring materials. The experimental results validate the effectiveness of the device.

Summary Bone defects caused by trauma and surgery are common clinical problems encountered by orthopedic surgeons. Thus, a hard-textured, natural-like biomaterial that enables encapsulated cells to obtain the much-needed biophysical stimulation and produce functional bone tissue is needed. Incorporating nanomaterials into cell-laden hydrogels is a straightforward tactic for producing tissue engineering structures that integrate perfectly with the body and for tailoring the material characteristics of hydrogels without hindering nutrient exchange with the surroundings. In this review, recent developments in inorganic nanocomposite hydrogels for bone tissue engineering that are of vital importance but have not yet been comprehensively reviewed are summarized.

Experimental investigation has been performed to study the film cooling performance of the cylindrical holes embedded in sine-wave shaped trench. The sine-wave shaped trench is got by changing the trailing edge of the transverse trench into sine-wave shape; the holes are located next to the peaks of the wave. The sine-wave shaped trench hole is expected to get a wider spread of the cooling jet in the span-wise direction. The film cooling effectiveness and discharge coefficient of the sine-wave shaped trench hole configurations with different trench depths (0.75D, 1D) and wave peaks (1D, 2D) have been measured using the transient thermal liquid measurement technique. The blowing ratio covers a range from 0.5 to 2.0. The transverse trench hole was also investigated as a basis of comparison. Thermal and hydrodynamic fields were investigated numerically using Reynolds Averaged Navier Stokes (RANS) simulations with realizable k-ε turbulence model and enhanced wall treatment. Results show that downstream the sine-wave shaped trench, the film cooling effectiveness is higher in the region between the holes. That’s due to the jet spread wider under the influence of the anti-counter-rotating vortices which caused by the sine-wave shape. With the increasing blowing ratio, the film cooling effectiveness of the sine-wave shaped trench hole increases. The larger trench depth produces higher film cooling effectiveness in the region between the holes. With the increasing wave peak, the film cooling effectiveness is increased in the region between the holes due to that more of the jet flows to the wave valley. The discharge coefficients of the sine-wave shaped trench configurations are higher than the transverse trench which means that the sine-wave shape trench has lower flow resistance.

The effects of nucleating agents on the morphology and performance of poly(vinylidene fluoride) (PVDF) microporous membranes via thermally induced phase separation were investigated. The nucleating agents studied were dicyclohexyl benzene amide (TMB-5), 2,2-methylene bis(4,6-tertiary butyl phenol) sodium phosphate (TMP-1), and 1,3 : 2,4-di-p-methylbenzylidene sorbitol (DM-LO). Light transmittance experiments and differential scanning calorimetry (DSC) were performed to obtain phase diagrams of PVDF/ tributyl citrate/di(2-ethylhexyl) phthalate/nucleating agent doped solutions. The morphology and performance of the prepared PVDF microporous membranes were characterized with scanning electron microscopy and microfiltration experiments. The results show that the thermodynamics of liquid-liquid phase separation were not affected by the addition of the nucleating agents, but solid-liquid phase separation was influenced. The system with 0.3 wt % TMB-5 had the fastest crystallization rate and a better nucleation ability. The PVDF microporous membranes had a partly closed, lacy bicontinuous structure with TMP-1 and DM-LO, whereas the membrane with 0.3 wt % TMB-5 had an interconnected bicontinuous structure. The pore size distribution became narrower with the addition of nucleating agent. With 0.3 wt % TMB-5, the membrane had the minimum mean pore size (0.095 lm), a porosity of 80.3%, and a pure water flux of 270 LÁm À2 Áh À1 ; these values were higher than those of the pure PVDF membrane. The performances of the membranes decreased with additions of TMB-5 of greater than 0.3 wt %.

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