Reliably predicting how coral calcification may respond to ocean acidification and warming depends on our understanding of coral calcification mechanisms. However, the concentration and speciation of dissolved inorganic carbon (DIC) inside corals remain unclear, as only pH has been measured while a necessary second parameter to constrain carbonate chemistry has been missing. Here we report the first carbonate ion concentration ([CO32−]) measurements together with pH inside corals during the light period. We observe sharp increases in [CO32−] and pH from the gastric cavity to the calcifying fluid, confirming the existence of a proton (H+) pumping mechanism. We also show that corals can achieve a high aragonite saturation state (Ωarag) in the calcifying fluid by elevating pH while at the same time keeping [DIC] low. Such a mechanism may require less H+-pumping and energy for upregulating pH compared with the high [DIC] scenario and thus may allow corals to be more resistant to climate change related stressors.

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Melt-crystallization of PBN was analyzed as a function of the crystallization conditions. Crystallization above 160 °C leads to formation of crystals and spherulites directly from the melt. Crystallization below 160 °C proceeds via intermediate formation of a smectic liquid crystalline (LC) phase. Cooling faster than 200-500 K/s suppresses crystal formation from the LC phase. The smectic LC phase exhibits a distinct Schlieren texture.

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In order to prepare polypropylene (PP) composites with balanceable stiffness and toughness, hybrid wollastonite with different nucleation and morphology as fillers were added into PP matrix. Nucleation efficiency (NE), crystallization behavior and melting characteristics, as well as the mechanical properties of hybrid wollastonite-filled PP composites were systematically investigated using differential scanning calorimetry, wide-angle X-ray diffraction, mechanical testing, and scanning electron microscopy, respectively. The results indicated that the NE of wollastonite with b-nucleation is much higher than that of acicular wollastonite and ultrafine wollastonite with a-nucleation, and eventually hybrid wollastonite-filled PP composites mainly form b-phase PP. Furthermore, there exists cooperative effect between the reinforcement of wollastonite of different morphology and the toughening of b-phase, which can be effectively controlled through regulating the nucleating ability, morphology, and mass ration of hybrid wollastonite. POLYM. COMPOS., 00:000-000, 2018.that the addition of AW and BW is able to enhance the stiffness of PP, and the b-phase induced by b-W can significantly improve the toughness of PP. It should be noted that the synergistic effect between b-W and AW is more effective for the improvement of impact strength of PP, while the synergistic effect between b-W and BW is better for the enhancement of PP stiffness. CONCLUSIONSAcicular wollastonite and ultrafine wollastonite present different degree of a-nucleation for the crystallization of FIG. 12. SEM images of B 0 (a), B 3 (b) and B 5 (c). FIG. 11. Impact strength of b-W/BW hybrid-filled PP composites. 8 POLYMER COMPOSITES-2018

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Wollastonite-filled a-isotactic polypropylene (iPP) and b-iPP were prepared through introduction of wollastonite (W) and wollastonite with b-nucleating surface (W x ) in iPP matrix. The a-and b-nucleating ability of wollastonite, crystalline morphology, and mechanical properties of injected iPP filled by wollastonite with different nucleating surface were compared using differential scanning calorimetry, wide-angle X-ray diffraction, polarizing optical microscopy, mechanical testing, and scanning electron microscopy. The results indicated that iPP filled by wollastonite with different nucleating surface has different crystalline morphology, melting behavior, and mechanical properties. The W and W x filled iPP mainly formed a-and b-phase iPP, respectively. The tensile and flexural modulus of iPP/W and iPP/W x increased with increasing wollastonite content, and the tensile and flexural modulus of iPP/W x were lower than that of iPP/W. The tensile property, flexural property, and impact strength of iPP/W x were higher than that of iPP/W and b-iPP. The synergistic effect of reinforcing of wollastonite and toughening of b-phase leads to higher mechanical properties. POLYM. COMPOS.,

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