Interaction of multicomponent disilicate (Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)2Si2O7 with molten calcia-magnesia-aluminosilicate

Environmental barrier coating (EBC) materials that are resistant against molten calcia-magnesia-aluminosilicate (CMAS) corrosion are urgently required. Herein, multicomponent rare-earth (RE) disilicate ((Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)2Si2O7, (5RE)2Si2O7) was investigated with regard to its CMAS interaction behavior at 1400 °C. Compared with the individual RE disilicates, the (5RE)2Si2O7 material exhibited improved resistance against CMAS attack. The dominant process involved in the interaction of (5RE)2Si2O7 with CMAS was reaction-recrystallization. A dense and continuous reaction layer protected the substrate from rapid corrosion at high temperatures. The results demonstrated that multicomponent strategy of RE species in disilicate can provide a new perspective in the development of promising EBC materials with improved corrosion resistance.

Brazing Si3N4 Ceramic to Molybdenum Using an Ag-Cu-Ti Filler

A Si3N4 ceramic was successfully joined to molybdenum(Mo) using an Ag-Cu-Ti filler alloy. The interfacial microstructure of the Si3N4/Ag-Cu-Ti/Mo joint was investigated by scanning an electron microscopy, energy dispersive spectrometer, and x-ray diffraction. The results showed the joint brazed at 900˚C for 10 min was smooth, and there were no holes and cracks at the interface. A continuous reaction layer, which is composed of TiN and TiSi2, was formed near the Si3N4 ceramic, with TiN being located near the ceramic. The central part of the joint was composed of Ag- and Cu-based solid solutions. At the side near the Mo metal, there was a formation of the MoTi solid solution. The typical structure of the Si3N4/Mo joint was Si3N4/TiN  TiSi2 reaction layer/Ag(s,s) Cu(s,s)/MoTi/Mo. Because TiN and TiSi2 com-pounds are generated on the ceramic side, the microhardness of the reaction layer on the ceramic side was de-creased but still much higher than the hardness of the brazing seam and the Mo base material. The shear strength of the brazed joint was 204 MPa at room temperature.

Cognitive Impairment In Stable Wilson Disease Across Phenotype.

Background: In Wilson disease (WD), mutations in the gene encoding the ATP7B copper transport protein causes accumulation of copper especially in liver and brain. WD typically presents with hepatic and/or neuropsychiatric symptoms. Impaired cognition is a well-described feature in patients neurological WD, while the reports on cognition in hepatic WD patients are fewer and less conclusive. We examined cognition in a cohort of WD patients with both phenotypes. Methods: In this cross-sectional pilot study, we investigated cognition in 28 stable Danish WD patients by portosystemic encephalopathy (PSE) and continuous reaction time (CRT) tests. Half of the patients were female and median age was 35.5 years (IQR 24.5). The phenotype was hepatic in 14 (50%), neurologic in 10 (36%) and mixed in 4 4 (14%). The duration of treatment was >2 year in all patients, and the condition stable as judged by urinary copper excretion, liver enzymes, and clinical assessment.Results: In total, 16 (57%) patients performed worse than normal in the PSE and/or CRT tests. The two tests correlated (rho=0.60, p=0.0007) with each other, but neither correlated with phenotype, MELD-, Child-Pugh score, 24h-U-Cu, or treatment type.Conclusion: Measurable cognitive impairment was present in more than half of the stable WD patients independent of phenotype. Thus, our data questions the existence of a purely hepatic phenotype.

Co-Promoted Ni Nanocatalysts Derived from NiCoAl-LDHs for Low Temperature CO2 Methanation

Ni-based catalysts are prone to agglomeration and carbon deposition at high temperatures. Therefore, the development of Ni-based catalysts with high activities at low temperatures is a very urgent and challenging research topic. Herein, Ni-based nanocatalysts containing Co promoter with mosaic structure were prepared by reduction of NiCoAl-LDHs, and used for CO2 methanation. When the reaction temperature is 250 °C (0.1 MPa, GHSV = 30,000 mL·g−1·h−1), the conversion of CO2 on the NiCo0.5Al-R catalyst reaches 81%. However, under the same test conditions, the conversion of CO2 on the NiAl-R catalyst is only 26%. The low-temperature activity is significantly improved due to Co which can effectively control the size of the Ni particles, so that the catalyst contains more active sites. The CO2-TPD results show that the Co can also regulate the number of moderately basic sites in the catalyst, which is beneficial to increase the amount of CO2 adsorbed. More importantly, the NiCo0.5Al-R catalyst still maintains high catalytic performance after 92 h of continuous reaction. This is due to the confinement effect of the AlOx substrate inhibiting the agglomeration of Ni nanoparticles. The Ni-based catalysts with high performance at low temperature and high stability prepared by the method used have broad industrial application prospects.

Catalytic hydrolysis of CFC-12 over MoO3/ZrO2 -TiO2 solid acid

The catalytic hydrolysis of Difluorodichloromethane(CFC-12) by solid acid of MoO3/ZrO2-TiO2 calcined at different temperature had been studied. The effects of catalytic hydrolysis temperature and water vapor concentration on catalytic hydrolysis of CFC-12were also studied. The results showed that catalytic hydrolysis rate of CFC-12 reached to 98.65% at 400 ℃ when the MoO3/ZrO2-TiO2 catalyst was calcined at 500 ℃ with a concentration of water vapor of 83.18%, and the main hydrolysis products were CO, CO2, HF and HCl. After 30 hours’ continuous reaction, the hydrolysis rate of CFC-12 was 65.34%. The XRD result reveals that the main phase of solid MoO3/ZrO2-TiO2 catalyst is the tetragonal Zr (MoO4)2 with doped TiO2 of anatase.

Catalytic hydrolysis of Dichlorodifluoromethane over MoO3/ZrO2 -TiO2 solid acid

The catalytic behaviors of solid acid of MoO3/ZrO2-TiO2 calcined at different temperature for the catalytic hydrolysis of Dichlorodifluoromethane have been studided. The effects of catalytic hydrolysis temperature and water vapor concentration on catalytic hydrolysis of Dichloro difluoromethane were also studied. The Results show 98.65 % of Dichlorodifluoromethane is degraded over MoO3/ZrO2-TiO2 catalyst calcined at 500 ℃ with a concentration of water vapor of 83.18% when the hydrolysis temperature is 350 ℃ and the Dichlorodifluoromethane flux rate is 1 mL/min with main degradation products were CO, CO2, HF and HCl. A maintained degradation rate of 65.34% of Difluoromethylene Chloride has been observed through 30 hours’ continuous reaction over the catalyst of MoO3/ZrO2-TiO2. The XRD result reveals the main phase of solid MoO3/ZrO2-TiO2 catalyst is the tetragonal Zr (MoO4)2 that dopedTiO2 of anatase.

Catalytic hydrolysis of Dichlorodifluoromethane over MoO3/ZrO2 -TiO2 solid acid

The catalytic hydrolysis of Difluoro dichloromethane (CFC-12) by solid acid of MoO3/ZrO2-TiO2 calcined at different temperature had been studied. The effects of catalytic hydrolysis temperature and water vapor concentration on catalytic hydrolysis of CFC-12 were also studied. The results showed that catalytic hydrolysis rate of CFC-12 reached to 98.65 % at 400℃when the MoO3/ZrO2-TiO2 catalyst was calcined at 500℃ with a concentration of water vapor of 83.18%, and the main hydrolysis products were CO, CO2, HF and HCl. After 30 hours’ continuous reaction, the hydrolysis rate of CFC-12 was 65.34%. The XRD result reveals that the main phase of solid MoO3/ZrO2-TiO2 catalyst is the tetragonal Zr (MoO4)2with doped TiO2 of anatase.

Catalytic hydrolysis of Dichlorodifluoromethane over MoO3/ZrO2 -TiO2 solid acid

The catalytic hydrolysis of Difluorodichloromethane(CFC-12) by solid acid of MoO3/ZrO2-TiO2 calcined at different temperature had been studied. The effects of catalytic hydrolysis temperature and water vapor concentration on catalytic hydrolysis of CFC-12were also studied. The results showed that catalytic hydrolysis rate of CFC-12 reached to 98.65 % at 400。C when the MoO3/ZrO2-TiO2 catalyst was calcined at 500℃ with a concentration of water vapor of 83.18% ,and the main hydrolysis products were CO, CO2, HF and HCl. After 30 hours’ continuous reaction, the hydrolysis rate of CFC-12 was 65.34%. The XRD result reveals that the main phase of solid MoO3/ZrO2-TiO2 catalyst is the tetragonal Zr(MoO4)2with dopedTiO2 of anatase.