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Enamel coating, which is of low thermal conductivity and high chemical stability, has been employed for the protection of many hot parts against oxidation. It is composed of multiple oxides, and each oxide component plays a certain role on thermophysical properties. In this paper, a type of silicate enamel coating with different contents of oxide component Al 2 O 3 was prepared on K444 superalloy. Its microstructural evolution and cyclic oxidation behavior at 1000 °C were investigated. Results indicated that the A0 enamel coating, which was free of Al 2 O 3 in composition, suffered from serious crystallization at high temperature. The formation of quartz, cristobalite and SrSiO 3 crystals resulted in significant mass loss during cyclic oxidation. However, precipitation of these crystals was almost completely prohibited in the A10 and A15 coatings with 10 and 15 wt% Al 2 O 3 , respectively. The A10 coating had no mass loss after cyclic oxidation. But much high content of Al 2 O 3 resulted in the formation of abundant long strip crystals of SrAl 2 Si 2 O 8 in the A15 coating, which led to minor spallation. Furthermore, enamel coatings with Al 2 O 3 (above 6 wt%) promoted the formation of a continuous alumina scale at the enamel/alloy interface, which improved oxidation resistance and increased bonding strength. The well grown alumina scale at interface as well as the mild crystallization ensured high spallation resistance of the enamel coating A10. [ABSTRACT FROM AUTHOR]

Herein, a multicomponent bioactive glass (0Z, 46SiO 2 –30CaO–18Na 2 O–6P 2 O 5 , wt.%) is prepared via melting. ZrO 2 is introduced into the bioglass using two different methods, and then three types of glass-ceramic bulks are manufactured using low-cost pressureless sintering. The effect of ZrO 2 addition on the bioactivity and mechanical properties of the bioactive glass-ceramic is assessed. The results indicate that the main crystalline precipitate from the bioactive glass-ceramic is Na 2 Ca(Si 2 O 6). The crystallisation ability of the 5Z glass-ceramic, bioactive glass-ceramic with ZrO 2 added during melting at high temperature, is reduced because ZrO 2 participated in the reconstruction of the glass network. Further, the ZrO 2 addition led to a low rate of cation release when soaked in simulated body fluid, indicating a decreased bioactivity. At the same time, the 5Y bioactive glass-ceramic, prepared by mixing YSZ particles with 0Z using ball-milling, possesses not only the highest mechanical strength (about twice the strength of 0Z) but also a high bioactivity. This study presents a promising method for the production of excellent bioactive glass-ceramic and a candidate (5Y) for the clinical applications where load bearing is required. [ABSTRACT FROM AUTHOR]

This paper considers both quenching and blowup phenomena to the coupled parabolic equations with zero Dirichlet boundary. Here, one component of the solution represents the density of some chemical and the other denotes its temperature in some ignition process. All the singular phenomena have been obtained including simultaneous and nonsimultaneous blow-up or quenching, which are classified completely by the exponents. The results extend the ones in the previous paper (Liu and Chan, 2011). [ABSTRACT FROM AUTHOR]

This paper deals with simultaneous blow-up solutions to a Dirichlet initial–boundary problem of the parabolic equations u t = div ( a ( x ) ∇ u ) + ∫ Ω u m v s d x and v t = div ( b ( x ) ∇ v ) + ∫ Ω u q v p d x in Ω × [ 0 , T ) . We complete the previous known results by covering the whole range of possible exponents. Then uniform blow-up profile is obtained for all simultaneous blow-up solutions through proving new rules for some auxiliary systems. At last, boundary layer is studied. [ABSTRACT FROM AUTHOR]

Photoaging is an important reaction for waste plastics in the aquatic environment and plays a key role in the lifetime of plastics. Nevertheless, when natural photosensitive substances such as nitrate participate in this process, the physiochemical changes in plastics and the corresponding reaction mechanisms are not well-understood. In this work, the photochemical behavior of polyethylene terephthalate (PET) bottles in deionized water and nitrate solution was systematically investigated under ultraviolet (UV) irradiation. The analyses of the surface physicochemical properties of the photoaged PET bottles indicated that, after 20 days of photo-irradiation, the presence of nitrate reduced the contact angle from 69.8 ± 0.9° to 60.0 ± 0.3°, and increased the O/C ratio from 0.23 to 0.32, respectively. The leaching rate of dissolved organic carbon (DOC), which was 0.0193 mg g−1·day−1 in nitrate solution, was twice that of 0.00941 mg g−1·day−1 in deionized water. Furthermore, fluorescence spectroscopy revealed that the increasing DOC had aromatic rings with hydroxyl on the side-chain formed after UV irradiation. The positive effect of nitrate on the degradation of PET bottles was mainly through the generation of hydroxyl radicals that were produced through the photolysis of nitrate. In addition, two-dimensional correlation spectroscopy analysis showed that the chain scission of PET plastics could be initiated by nitrate-induced ·OH attacking the carbon-oxygen bonds instead of forming peroxides with oxygen. This work elucidates the mechanism of photodegradation of plastics that was induced by nitrate and highlights the important role of natural photosensitive substances in the photoaging process of plastics. [Display omitted] • The photodegradation of polyethylene terephthalate (PET) was accelerated by nitrate. • Hydroxyl radicals (·OH) induced by nitrate contributed to the PET photodegradation. • Humic-like dissolved organic matters released from aged PET under ultraviolet light. • A new pathway for photodegradation of PET plastics occurred in the nitrate solution. [ABSTRACT FROM AUTHOR]

Iron oxides play an important role in the transport and transformation of organic phosphorus in aquatic environments. However, the effect of different types of iron oxide on the environmental fate of organic phosphorus has remained unclear. In this study, the photodegradation of the organic phosphorus compound adenosine triphosphate (ATP) via the activity of crystalline (goethite) and amorphous (ferrihydrite) iron oxides was investigated. It was found that ATP was photodegraded by goethite, resulting in the release of dissolved inorganic phosphate under simulated sunlight irradiation. The concentration of ATP on goethite decreased by 75% after 6 h of simulated sunlight irradiation, while the concentration of ATP on ferrihydrite decreased by only 22%. ATR-FTIR spectroscopy revealed that the intensity of the peaks for the P–O and P O stretching vibrations in the goethite−ATP complex decreased significantly more after simulated sunlight irradiation than did those for the ferrihydrite treatment. Combined with the higher TOC/TOC 0 values for the goethite treatment, the results indicate that a more vigorous photochemical reaction took place in the presence of goethite than with ferrihydrite. Reactive oxygen species analysis also showed that hydroxyl and superoxide anion radicals were generated when goethite was exposed to simulated sunlight irradiation, while ferrihydrite did not exhibit this ability. Overall, this study highlights that the type of iron oxide is an important factor in the transformation of organic phosphorus in aquatic environments. [Display omitted] • Transformation of organic phosphorus after adsorption was investigated. • Organic phosphorus adsorbed on goethite underwent photodegradation. • •OH and O 2 •− generated on the gothite, but not ferrihydrite. • Iron minerals mediated the environmental fate of organic phosphorus. [ABSTRACT FROM AUTHOR]

Abstract: This work deals with non-simultaneous and simultaneous blow-up solutions for , , subject to homogeneous Dirichlet boundary conditions. We obtain the complete results of non-simultaneous and simultaneous blow-up solutions for any fixed point in any general bounded domain. The critical exponents of non-simultaneous blow-up are proposed. [Copyright &y& Elsevier]

Abstract: This work deals with heat equations coupled via nonlinear boundary flux which obey different laws. We give a complete classification for non-simultaneous and simultaneous blow-up by covering all of the possible exponents. [Copyright &y& Elsevier]

Abstract: This paper deals with a reaction-diffusion equation with inner absorption and boundary flux of exponential forms. The blow-up rate is determined with the blow-up set, and the blow-up profile near the blow-up time is obtained by the Giga–Kohn method. It is observed that the blow-up rate and profile are independent of the nonlinear absorption term. [Copyright &y& Elsevier]

Haplogroup G predisposes one to an increased risk of osteoarthritis (OA) occurrence, while haplogroup B4 is a protective factor against OA onset. However, the underlying mechanism is not known. Here, by using trans-mitochondrial technology, we demonstrate that the activity levels of mitochondrial respiratory chain complex I and III are higher in G cybrids than in haplogroup B4. Increased mitochondrial oxidative phosphorylation (OXPHOS) promotes mitochondrial-related ATP generation in G cybrids, thereby shifting the ATP generation from glycolysis to OXPHOS. Furthermore, we found that lower glycolysis in G cybrids decreased cell viability under hypoxia (1% O 2 ) compared with B4 cybrids. In contrast, G cybrids have a lower NAD + /NADH ratio and less generation of reactive oxygen species (ROS) under both hypoxic (1% O 2 ) and normoxic (20% O 2 ) conditions than B4 cybrids, indicating that mitochondrial-mediated signaling pathways (retrograde signaling) differ between these cybrids. Gene expression profiling of G and B4 cybrids using next-generation sequencing technology showed that 404 of 575 differentially expressed genes (DEGs) between G and B4 cybrids are enriched in 17 pathways, of which 11 pathways participate in OA. Quantitative reverse transcription PCR (qRT-PCR) analyses confirmed that G cybrids had lower glycolysis activity than B4 cybrids. In addition, we confirmed that the rheumatoid arthritis pathway was over-activated in G cybrids, although the remaining 9 pathways were not further tested by qRT-PCR. In conclusion, our findings indicate that mtDNA haplogroup G may increase the risk of OA by shifting the metabolic profile from glycolysis to OXPHOS and by over-activating OA-related signaling pathways. [ABSTRACT FROM AUTHOR]

• Tribo-corrosion of stainless steel in molten zinc alloy is studied. • Without wear, Fe2Al5Znx layer forms and protects steel from dramatic corrosion. • The synergy of corrosion and wear accounts for 90 % of material loss. • Corrosion induces brittle scale and embrittlement at subsurface, accelerating wear. • Wear promotes formation of less-protective FeZn 10 scale, accelerating corrosion. The failure of 316 stainless steel under tribo-corrosion in molten zinc alloy (Zn-0.2Al, wt%) at 460 °C was investigated and compared with corrosion or the sole wear. In the absence of wear, intact Fe 2 Al 5 Zn x layer forms and protects the steel from dramatic corrosion. Without liquid-metal corrosion, the steel suffers from plastic deformation on friction and slight adhesive wear. While for tribo-corrosion, the synergy of corrosion and wear accounts for 90 % of material loss. Firstly, corrosion generates a brittle scale and leads to embrittlement at subsurface, which accelerate wear. Secondly, wear promotes the formation of less-protective FeZn 10 scale, accelerating corrosion. [ABSTRACT FROM AUTHOR]

This paper deals with a reaction–diffusion equation with nonlocal inner source and nonlocal boundary flux. Besides the influence of exponents, we find out that the weighted functions and the measure of the domain could lead to the existence of global solutions for any initial data. Larger weighted functions require smaller initial data in guaranteeing the existence of global solutions to the problem. Blow-up rates are obtained under different dominations of nonlinearities in one dimensional space. The upper and lower bounds of blow-up time are determined for all spatial dimensions, respectively. Moreover, the solutions blow up only on the boundary when the nonlocal flux dominates the blow-up. [ABSTRACT FROM AUTHOR]

In order to reduce contamination levels from diverse sources, it is important to understand the factors affecting the natural ecosystems that are impacted by coastal and marine pollution. In this study, we used GIS and remote sensing techniques to investigate and evaluate the distribution of heavy metals (Fe, Mn, Zn, Cr, Pb, Co, and Cu) in surface sediments along Tamil Nadu's East Coast (from Besant Nagar to Sathurangapattinam). The CF and Igeo of metals indicate that sediments contain no evidence of Fe, Mn, or Zn metal pollution in the sediments, with only mild contamination from Co, Cu, and Pb. In contrast, the sediment samples were found to be significantly contaminated with Cr. Heavy metal contamination occurs in the following order, according to our research: Cr > Pb > Cu > Co > Mn > Zn > Fe. Except for sites 8, 10, 11, and 13, where PLI>1 implies that there is no pollution in this area, the PLI values show that most of the locations are contaminated. The ecological risk index (ERI) values for five metals in the study areas are as follows: Cr > Pb > Cu > Mn > Zn. The sediment samples fall into the low-risk and highly polluted to dangerous sediment categories for SPI, according to the Risk index (RI). Based on the Mean Effect Range-Median Quotient (M-ERM-Q), Cu, Pb, Zn, and Cr metals in the research region have a 9–21% probability of being harmful. Statistical approaches show that the majority of heavy metals in sediments are of natural origin. The spatial distribution of heavy metals in surface sediments provides the conceptual framework for practical strategies to protect coastal areas. Many shreds of evidence indicate that anthropogenic inputs from the surrounding land area are primarily responsible for the deposition of these heavy metals in the coastal zone. [Display omitted] [ABSTRACT FROM AUTHOR]