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Abstract: The urokinase receptor (uPAR) serves as a docking site to the serine protease urokinase-type plasminogen activator (uPA) to promote extracellular matrix (ECM) degradation and tumor invasion and metastasis. Previously, we had reported a small molecule inhibitor of the uPAR·uPA interaction that emerged from structure-based virtual screening. Here, we measure the affinity of a large number of derivatives from commercial sources. Synthesis of additional compounds was carried out to probe the role of various groups on the parent compound. Extensive structure-based computational studies suggested a binding mode for these compounds that led to a structure–activity relationship study. Cellular studies in non-small cell lung cancer (NSCLC) cell lines that include A549, H460 and H1299 showed that compounds blocked invasion, migration and adhesion. The effects on invasion of active compounds were consistent with their inhibition of uPA and MMP proteolytic activity. These compounds showed weak cytotoxicity consistent with the confined role of uPAR to metastasis. [Copyright &y& Elsevier]

Porcine reproductive and respiratory syndrome (PRRS) is one of the major drivers of economic loss in the swine industry worldwide. In commercial pig production, vaccination is the first option in an attempt to control infectious diseases. Pigs are therefore often immunized with different vaccines, and almost all of them are delivered via the intramuscular (IM) route. However, the IM injection may result in physical damage, stress reactions, and is labor demanding. An alternative route is urgently needed to reduce the disadvantages of conventional vaccination. In this study, a needle-free intradermal (ID) delivery system was evaluated for delivering a live PRRS vaccine as compared with the traditional needle-syringe method. Fifty-two 4-week-old piglets were divided into six groups: piglets in groups A-C were immunized using ID delivery system with 104, 105 and 106 TCID 50 of PRRS candidate vaccine strain rHN-NP49, respectively; piglets in group D were immunized IM with 105 TCID 50 of rHN-NP49; and group E and F were used as challenge and control groups, respectively. At 28 days post vaccination, piglets in group A to E were challenged with a lethal dose of highly-pathogenic PRRSV. Similar results were found in viremia and antibody response among the ID and IM groups during the immunization stage. After challenge, similar results were found in average body weight gain, viral shedding, serum viral load, and clinical score among the immunization groups, with a higher protection ratio in the ID group compared with IM group with the same immunization dose. These results demonstrated that the ID delivery system could provide similar or even better protection compared with IM route, and could be an effective route for PRRS vaccination. [ABSTRACT FROM AUTHOR]

The tin bronze- x Cr 3 C 2 -graphite composites (x = 5, 10, 15, and 20 wt%) were fabricated by mechanical alloying and spark plasma sintering. Fine-scale uniform distribution of composites was achieved. The Cr 3 C 2 particles enhanced the mechanical properties and wear resistance of copper-based composites. The as-sintered tin bronze-20Cr 3 C 2 -graphite showed a hardness of 109 HV, a compressive strength of 333 MPa, and a yield strength of 219 MPa. In addition, the wear rate of as-sintered tin bronze-20Cr 3 C 2 -graphite was maintained in the order of 10−5 at 30 N, 50 N, and 70 N. The wear mechanism of the studied composites varied from surface fatigue and adhesion wear to abrasive wear with the increase of Cr 3 C 2 content during dry sliding. These findings provide a new method for developing copper-based composites with enhanced mechanical properties and wear resistance. • The tin bronze-Cr 3 C 2 -graphite composites were fabricated by powder metallurgy. • The Cr 3 C 2 particles enhanced the mechanical properties and wear resistance of copper-based composites. • The wear mechanism of the studied composites varied with the increase of Cr 3 C 2 content. [ABSTRACT FROM AUTHOR]

• rPRRSV-E2 immunized piglets developed high levels of antibodies against HP-PRRSV and CSFV. • Immunized pigs were well protected from the challenge of HP-PRRSV or CSFV at 20 weeks and 24 weeks post vaccination. • The immune duration of rPRRSV-E2 is at least 5 months against both HP-PRRSV and CSFV. Classical swine fever virus (CSFV) and Porcine reproductive and respiratory syndrome virus (PRRSV) are both important pathogens which seriously harm the economic swine industry worldwide. We have previously demonstrated that rPRRSV-E2 is a promising live, virus-vectored vaccine that provides 100% protection against highly pathogenic PRRSV (HP-PRRSV) and CSFV. Here, we evaluated the duration of immunity (DOI) of the vaccine strain, rPRRSV-E2. Vaccine or cell culture medium was administered to piglets at 4 weeks of age. All immunized piglets developed high levels of antibodies, which could maintain for up to 23 weeks, against PRRSV and CSFV. All immunized pigs were well protected from the challenge of HP-PRRSV or CSFV at 20 weeks and 24 weeks post vaccination. The vaccine protection rate was still 100% at 24 weeks after immunization. The immune efficacy results showed that the immune duration of rPRRSV-E2 could be up to 5 months. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome (PRRS) and classical swine fever (CSF) are economically significant diseases that affect the swine industry worldwide. However, the current vaccination strategy, which uses two single live attenuated vaccines, can result in interference for each other. In addition, the universally used CSFV vaccine C-strain does not allow for differentiation of infected and vaccinated animals. In this study, rPRRSV-E2, PRRS virus (PRRSV) expressing CSF virus (CSFV) E2, was constructed by reverse genetics. The E2 gene of CSFV was inserted between ORF1b and ORF2 in the genome of the PRRS vaccine virus, HuN4-F112. A copy of transcriptional regulatory sequence 6 was inserted at the 3′ terminal of the exogenous gene to produce CSFV E2 as a unique subgenomic mRNA transcript. The rPRRSV-E2 was stable for at least 25 serial cell passages. Single-shot intramuscular immunization of rPRRSV-E2 into pigs induced PRRSV-specific and CSFV-specific antibodies and fully protected pigs from lethal challenge with highly-pathogenic PRRSV and CSFV. These results demonstrate that a novel strategy for recombinant PRRSV production is effective, and suggest that rPRRSV-E2 is a promising live, virus-vectored vaccine against PRRS and a marker vaccine against CSF. [ABSTRACT FROM AUTHOR]

A series of thermally stable α-alumina supported and unsupported ceria catalysts with varying composition is systematically investigated under realistic coke – catalyst contact conditions for the oxidation of in-situ generated coke during ethylene pyrolysis. These catalysts have been designed for use in high temperature applications of steam cracking. The textural and structural characterization of α-alumina supported ceria catalysts show the absence of solid oxide solutions, with the supported catalysts having distinct ceria domains on the alumina support. For comparison, two types of coke – catalyst contacting are explored: (i) tight contact by grinding industrial coke with catalyst and (ii) realistic in-situ contact, where coke is deposited on the catalytic support. During in-situ coke deposition, ceria-containing catalysts demonstrate resistance to coking as compared to the bare α-alumina support. Ceria and ceria – alumina composites also enabled coke oxidation at lower temperatures than the un-catalyzed coke oxidation. The presence of both Ce 3+ and Ce 4+ is confirmed by X-ray absorption near edge structure (XANES), consistent with the well-known redox capability of ceria catalysts. Kinetic studies revealed 50–80 mol% Ce as the best compositions for oxidation activity towards both industrial and in-situ coke. The catalytic activity correlates with the presence of reactive lattice oxygen atoms on ceria for both types of contact, indicating a similar mechanism of carbon oxidation under in-situ contact and tight contact conditions. A mechanism of reaction involving lattice oxygen of ceria is proposed for the oxidation of coke as well as for retardation of coke deposition on ceria domains. [ABSTRACT FROM AUTHOR]

A series of cerium-zirconium mixed oxides doped with alkaline earth metals was prepared by calcining a mixture of Ce 0.8 Zr 0.2 O 2 and the nitrate salt of alkaline earth metals at 1173 K. The results from X-ray diffraction, Raman spectroscopy and analytical electron microscopy indicated the alkaline earth compounds were dispersed on the surface of Ce 0.8 Zr 0.2 O 2 . The doped mixed oxides were evaluated in the catalytic reaction of solid coke under tight contact conditions with 10 vol.% O 2 in He at 693 K and with 100 vol.% H 2 O at 993 K using thermogravimetric analysis. For coke oxidation with O 2 , the weight loss was first order in coke, and the measured first order rate constant was proportional to the total surface area of catalyst at low catalyst loadings. For coke gasification with H 2 O, the weight loss was nearly zero order in coke, and the measured areal reaction rate was independent of the total surface area of catalyst at low catalyst loadings. The addition of alkaline earth metals inhibited coke oxidation with dioxygen but promoted coke gasification with steam. [ABSTRACT FROM AUTHOR]

The OC/EC online monitoring campaign was carried out in Tianjin of China from 8th February to 15th March 2015 during the Chinese Spring Festival period (CSFP). The concentrations of OC, EC, BC and other ambient pollutants (e.g. SO 2 , NO 2 and PM 2.5 , etc.) in high time resolution were measured with related online-monitoring instruments. During the CSFP, according to the peaks of PM 2.5 concentrations and number concentrations (NC) of aerosol particles with aerodynamic diameters between 0.3 and 2.5 μm, five pollution-events were generally identified and displayed. These pollution-events were closely associated with large-scale fireworks displaying, combustion activities such as heating for winter, and the stable meteorological conditions, etc. During the CSFP, EC and OC concentrations showed variations up to one order of magnitude. The uncertainty of instrument itself and the difference for measured methods, further caused the differences between thermal OC (measured OC by thermal method) and optical OC (measured OC by optical method) concentrations, as well as between thermal EC (measured EC by thermal method) and optical EC (measured EC by optical method) concentrations. The high-concentration carbonaceous aerosols could enlarge the uncertainty of measuring instrument, reducing the correlations between OC and EC, and enhance the differences among thermal EC, optical BC and optical EC. The OC/EC ratios and the percentages of SOC/OC would be declined, when the pollution-events formed during the CSFP. Due to the different sources for thermal POC and thermal SOC, the correlation of the two was relatively lower (R 2 = 0.39). Thermal POC dominated over thermal OC during the CSFP. [ABSTRACT FROM AUTHOR]

This paper presents an effective design solution for current-shunt monitor (CSM) adapting to both positive and negative power supply applications, where the supply voltage is input common-mode voltage (CMV) of CSM ranged from − 16 to 60 V. The proposed CSM mainly consists of a high-voltage low-drop output (HVLDO) regulator, a CSM core, and a 2nd-stage gain generator. The HVLDO regulator converts the independent supply voltage (5-16 V) to a stable internal output supply voltage of 5 V for other consequent circuits. The proposed CSM core adopts a fully-differential amplifier, a single-ended output amplifier, current-mirror transistors, and several resistors to constitute a stable negative feedback system. Due to its stable operation, the CSM core with both positive and negative CMV can successfully detect drops across the shunt resistor. The 2nd-stage generator is used to achieve a higher gain. By selecting proper transistor and resistor size in both CSM core and 2nd-stage gain generator, a total scaled gain of 100 V/V is achieved in this study. The proposed CSM architecture has been successfully implemented in a 0. 25 μ m Bipolar-CMOS-DMOS (BCD) technology, and the area is around 1.44 mm 2. Measurements show that the proposed CSM with an input CM voltage ranged from -16–60 V can sense an input voltage difference 4–16 mV. [ABSTRACT FROM AUTHOR]

As the need for renewable and high-performance alternative elastomer grows, efforts have been made to develop bio-based elastic polymers for engineering applications. Herein, bio-based elastomers poly(dimethyl itaconate- co -butadiene)s (PDMIBs) were successfully synthesized by emulsion copolymerization of renewable monomer dimethyl itaconate (DMI) with partially petroleum-derived butadiene under mild conditions. It is an effective strategy to tailor PDMIB properties by comonomers with different feed ratios and to adjust the compositions and sequence distributions. The structure and thermal stability were investigated by FTIR, NMR, DSC analyses, etc. In terms of properties: (1) the vulcanizates showed excellent tensile strength (10.2 MPa), elongation at break (1146%) and toughness (37.6 MJ m−3) without filler reinforcement, which were obviously superior to the mechanical properties of most traditional petroleum-based synthetic rubbers; (2) Nanosilica-filled PDMIBs exhibited good mechanical properties, excellent abrasion resistance and oil resistance due to strong polarity in molecular chains; (3) Epoxy-functionalized poly(dimethyl itaconate- co -butadiene- co -glycidyl methacrylate) PDMIBG showed better silica dispersion and excellent dynamic mechanical properties. In summary, this new kind of bio-based elastomer PDMIBs can be used in multiple engineering applications, such as bio-based gloves, conveying belts, oil-resistant products and high-performance tire tread materials, etc. This study opens the door to the use of emulsion copolymerization and functionalization modification technology in the synthesis of new high-performance bio-based elastomer nanocomposites for the rubber industry. Novel sustainable elastomers nanocomposites with versatile properties are constructed based on bio-based dimethyl itaconate. [Display omitted] [ABSTRACT FROM AUTHOR]

Cubic boron nitride (cBN) composites, using Al and HfC as the additives, were sintered under static high pressure of 5.0 GPa and at temperatures of 700 °C–1500 °C for 80 s. By analyzing the phase components of the sintered samples through the X-ray diffraction (XRD) analysis, we found that when the temperature increased from 700 °C to 900 °C, cBN reacted with Al and HfC, and produced AlN, AlB 2 , HfB 2 and B 2 C 5 N 2 . Above 1000 °C, AlB 2 was not stable. It decomposed and finally generated AlB 12 . At the meantime, the content of AlN, AlB 12 , HfB 2 and B 2 C 5 N 2 increased with Al disappearing. The Vickers hardness of the sintered samples increased with increasing the cBN content. The SEM and the abrasion ratio tests revealed that the well-sintered samples with homogeneous microstructure and the best wear resistance could be obtained at 5.0 GPa, 1300 °C for 80 s with the cBN content of 80 wt.%. [ABSTRACT FROM AUTHOR]

Protein tyrosine phosphatases (PTPs) are important regulator of neuronal signal transduction and a growing number of PTPs have been implicated in Alzheimer's disease (AD). In the brains of patients with AD, there are a variety of abnormally phosphorylated proteins, which are closely related to the abnormal expression and activity of PTPs. β-Amyloid plaques (Aβ) and hyperphosphorylated tau protein are two pathological hallmarks of AD, and their accumulation ultimately leads to neurodegeneration. Studies have shown that protein phosphorylation signaling pathways mediates intracellular accumulation of Aβ and tau during AD development and are involved in synaptic plasticity and other stress responses. Here, we summarized the roles of PTPs related to the pathogenesis of AD and analyzed their therapeutic potential in AD. [Display omitted] • Protein tyrosine phosphatases (PTPs) are important regulator of neuronal signal transduction. • PTPs related to the pathogenesis of Alzheimer's disease (AD). • Compounds targeting PTPs alleviated pathological features of brain disease. • PTPs is expected to be an important direction and a potential breakthrough for AD research. [ABSTRACT FROM AUTHOR]

[Display omitted] • The carbon nanotube/oxygen-defective MnO 2 composite was designed as an effective sulfur host material. • The continuous carbon nanotube skeleton facilitates electron transport. • The oxygen-defective MnO 2 exhibits successful lithium polysulfides adsorption and catalysis process. • The resulting sulfur cathode delivers stable cyclic performance. The incorporation of sulfur with multifunctional conductive host material has been regarded as a promising strategy to improve the sulfur utilization and mitigate the polysulfides diffusion for high-performance Li-S battery. Herein, an oxygen-defective MnO 2 nanoparticles modified carbon nanotube composite (CNT/OD-MnO 2) has been proposed as multifunctional sulfur host materials. In the CNT/OD-MnO 2 , the continuous CNT frameworks provide abundant conduction paths of electrons, and the oxygen-defective MnO 2 nanoparticles can accelerate the adsorption and conversion process of polysulfides during the charge–discharge process. As expected, the derived sulfur cathode exhibits superior electrochemical properties with the assistance of CNT/OD-MnO 2. Compared with the CNT/MnO 2 -S (61.8%) and CNT-S (38.8%) cathodes, the CNT/OD-MnO 2 -S cathode delivers a higher capacity retention of 81.3% even after 300 cycles. These results confirm the promising application of CNT/OD-MnO 2 as an effective sulfur host material for advanced Li-S battery. [ABSTRACT FROM AUTHOR]

Abstract: Diffusion of water and ethanol in silicalite has been studied in large crystals (70μm×30μm×15μm) synthesized via a fluoride mediated route. The near-perfect hydrophobic silicalite (F−) crystals have very few internal silanol defects and, as a result, display water and ethanol transport behavior that is uncontaminated by these defects. The transport diffusivity (Dt ) of ethanol is higher than that of water at the same sorbate activity. However, this difference is due to the difference in the shape of the isotherms. The thermodynamically corrected diffusivity (D o) of water is almost an order of magnitude higher than that of ethanol reflecting the difference in molecular size. Estimates of the permeability/permselectivity/separation factors for ethanol/water separation based on the present kinetic and equilibrium data for the fluoride synthesized crystals are compared with the values observed for traditional silicalite membranes. The present diffusivity values for fluoride synthesized silicalite are similar to the values for regular silicalite (OH−) derived from uptake rate measurements but much smaller (by more than four orders of magnitude) than the self-diffusivities derived from PFG-NMR measurements. This result is consistent with the results of other measurements of the diffusion of small molecules in silicalite which suggest that, in macroscopic measurements, the rate of intra-crystalline transport is controlled by the sub-structure (extensive twinning), rather than by diffusion in the ideal MFI micropores. In this situation microscale measurements such as PFG-NMR will lead to erroneously high estimates of transport rates and therefore of permeability and permselectivity. [Copyright &y& Elsevier]

Abstract: This paper reports a facile method for the preparation of nitrogen-doped carbon nanotubes (N-doped CNTs) that shows enhanced hydrogen storage capacity. The synthesis method involves simple pyrolysis of melamine using FeCl3 as catalyst in tube furnace. The materials were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, elemental analysis, Raman spectroscopy, and nitrogen adsorption–desorption analysis. The results indicated that the prepared N-doped CNTs have a bamboo-like structure with thin compartment layers. The nitrogen doping concentration, specific surface area, and total pore volume of the N-doped CNTs were determined to be 1.5 at%, 135 m2/g, and 0.38 cm3/g, respectively. The hydrogen adsorption measurements at 77 K showed that the N-doped CNTs exhibits gravimetric hydrogen uptake of 0.21 wt% at 1 bar and 1.21 wt% at 7 bar. At room temperature, hydrogen uptake as high as 0.17 wt% at 298 K and 19 bar is achieved, which is among the highest data reported for the N-doped carbon materials under the same condition. [Copyright &y& Elsevier]

Abstract: Leptospirosis, caused by different Leptospira species, is one of the most widespread zoonotic infections worldwide. Here we expressed three major leptospiral lipoproteins and examined their immunogenicity. All the pathogenic Leptospira strains tested possess the lipL21, lipL32 and lipL41 genes, but the latter two can be further divided into different gene types (lipL32-1, lipL32-2, lipL41-1, lipL41-2). Microscopic agglutination test revealed that rLipLs antisera had extensive cross-immunoagglutination among the 178 leptospiral strains in which rLipL32-1 contributed the highest agglutination titer. The rLipLs-based ELISAs established in this study demonstrated that in the sera of 385 leptospirosis patients infected with different serovars of Leptospira interrogans, rLipL32-1 had the highest positive rates for IgG and IgM (89.4–98.7%), followed by the IgG/IgM positive rates of rLipL21 (87.0–96.1%) and rLipL32-2 (86.5–96.9%), while the two rLipL41s presented the lowest IgG/IgM positive rates (69.9–83.9%). The immunoprotective levels in guinea pigs of rLipL32-1 (58.3% and 66.7%) were the highest, compared to those of the other rLipLs (25.0–58.3%). Multiple different rLipLs would increase immunoprotective levels (from 58.3% and 66.7% to 83.3% and 91.7%). The data suggest that all the rLipLs are the genus-specific superficial antigens of pathogenic Leptospira species and should be considered in designing universal vaccines against leptospirosis. [Copyright &y& Elsevier]

• PRV infection leads to endogenous OASL downregulation. • RIG-I is required for OASL-mediated anti-PRV activity. • OASL exerts inhibitory effects on PRV proliferation. • PRV UL24 impairs RIG-I signaling. • PRV UL24 reduces OASL transcription in an IRF3-dependent manner. Oligoadenylate synthetases-like (OASL) protein exerts various effects on DNA and RNA viruses by inhibiting cGAS-mediated IFN production and by enhancing RIG-I-mediated IFN induction, respectively. In this study, we aimed to examine the role of OASL in pseudorabies virus (PRV) proliferation and investigate the function of the PRV UL24 protein in cellular innate immunity. We found that OASL regulates PRV proliferation by enhancing RIG-I signaling. PRV infection decreased the expression of OASL at both the mRNA and protein levels in PK15 and HeLa cells. OASL expression suppressed the proliferation of PRV in a RIG-I-dependent manner and boosted RIG-I-mediated IFN expression as well as IFN-stimulated gene (ISG) induction. In contrast, knockdown of OASL enhanced PRV proliferation and reduced RIG-I signaling. However, the PRV UL24 protein was found to impair RIG-I signaling, thus inhibiting transcription of IFN and ISGs. In addition, the UL24 protein reduced RIG-I-induced expression of endogenous OASL in an IRF3-dependent manner, thereby antagonizing the OASL antiviral effect. Taken together, our findings characterize the role of OASL in PRV proliferation and provide new insights into the role of UL24 in PRV pathogenesis. [ABSTRACT FROM AUTHOR]

• Crude carbon dots (CCDs), without any purification, were used as antioxidants for NR. • CCDs fluid was prepared by simply mixing the CCDs and water, and subsequent compounding of CCDs fluid and NR were reported. • The introduction of BR-g-MAH could effectively promote the CCDs dispersion within the NR matrix and enhance the interfacial bonding between CCDs and NR. • The CCDs could effectively improve the anti-aging performance of the rubber composites. Natural rubber (NR) is acknowledged to be a strategically important material, which spans multiple applications from tires to shock absorbers, generally, the antioxidant is indispensable for NR to prolong the service life and improve the long-term reliability. Recent reports demonstrated that the purified carbon dots with the capability of scavenging oxy radicals can be effective antioxidants for rubbers. However, the application of purified CDs is greatly restricted by the multiple tedious, complicated, time-consuming, and expensive post-purification processes. Herein, we first synthesize the amine-passivated crude carbon dots (CCDs) by a facile microwave-assisted pyrolysis method, and we attempt to directly use the CCDs (without any purifications) as a novel and inexpensive antioxidant for NR. To achieve a fine CCDs dispersion within NR matrix, we disperse the CCDs into the NR matrix by the liquid feeding and in-situ compatibilizing. The CCDs fluid was firstly prepared by mixing the CCDs with water, then the CCDs fluid together with the compatibilizer was melt-compounded with NR. The results showed that the well-dispersed CCDs endowed NR with the impressive antioxidative property. Overall, this work extends application scope of CCDs and provides unique inspiration to develop novel and effective antioxidants for elastomers. [ABSTRACT FROM AUTHOR]

• rPRRSV-E2 is a marker vaccine for CSFV. • rPRRSV-E2 is promising as a virus-vectored vaccine against both HP-PRRSV and CSFV infection in swine herds by single vaccination. • Maternal derived antibodies (MDAs) do not interfere with the immune efficacy of rPRRSV-E2. Currently live attenuated porcine reproductive and respiratory syndrome (PRRS) and classical swine fever (CSF) vaccines are widely used in Chinese swine herds. However, the mutual effects of vaccination procedures and severe stress caused by successive vaccinations harm piglets and make it difficult to stimulate robust and effective immune responses. In our previous study, a recombinant PRRS virus (PRRSV) vectored vaccine candidate rPRRSV-E2, which expresses CSF virus (CSFV) E2 protein, has been demonstrated being able to protect piglets against lethal challenge of highly-pathogenic (HP)-PRRSV and CSFV. In this study, we determine whether preexisting maternally derived antibodies (MDA) interfere with the immune efficacy of rPRRSV-E2. 8 experimental groups of piglets, with or without PRRSV MDAs or CSFV MDAs were immunized with a single dose of 105 TCID 50 rPRRSV-E2 or DMEM and challenged with HP-PRRSV or CSFV. Clinical characteristics, PRRSV- or CSFV-specific antibodies, viremia and pathological changes were monitored, examined and analyzed. The results showed that rPRRSV-E2-vaccinated piglets, either with or without MDAs directed against PRRSV or CSFV were completely protected from the lethal challenge of HP-PRRSV or CSFV. These results demonstrate that the MDAs do not interfere with the immune efficacy of rPRRSV-E2, which indicates that rPRRSV-E2 could have great significance in the effective prevention and control of HP-PRRSV and CSFV. [ABSTRACT FROM AUTHOR]

• Both NiAl 2 O 4 and NiCr 2 O 4 were stable during ethylene steam reforming at 873 K. • Both Fe and Ni in the NiFe 2 O 4 spinel catalyst reduced during steam reforming. • The NiFe 2 O 4 spinel catalyst severely coked during ethylene steam reforming. • The reforming rate increased after oxidation of the spent NiAl 2 O 4 and NiCr 2 O 4. Spinel oxides containing Ni cations can be present in the barrier layers of ethane steam cracker tubes. As Ni is known to catalyze steam reforming side reactions as well as coke deposition, the catalytic performance of Ni spinel catalysts was investigated. A series of NiM 2 O 4 spinel catalysts (M = Al, Cr, Fe) was synthesized from a sol-gel method and thoroughly characterized. The NiAl 2 O 4 and NiCr 2 O 4 catalysts were active for ethylene steam reforming at 873 K without degradation of the spinel structure. The NiFe 2 O 4 catalyst was the least stable because of partial reduction of Fe3+ to form Fe 3 O 4 , which facilitated Ni-Fe alloy particle formation and severe coking. The reforming activity and the coke deposited on the NiAl 2 O 4 and NiCr 2 O 4 catalyst both increased after oxidative regeneration at 873 K, suggesting a slow reduction of Ni2+ to Ni metal particles during steam reforming that subsequently sinter into larger NiO particles during oxidative regeneration. [ABSTRACT FROM AUTHOR]

• A hybrid model for PEMFC systems with water transport equivalent is developed. • Parameters of the developed model are identified by a regional expansion method. • The hypothesis of cathode micro-flooding operation of the PEMFC system is confirmed. • The influence of cathode micro-flooding on PEMFC performance is analyzed. • Differential current injection based self-healing control is discussed. In this paper, the influence mechanism of proton exchange membrane hydration dynamics on the output characteristics of the commercial integrated 150 kW proton exchange membrane fuel cell (PEMFC) systems was investigated under actual operating conditions. On this basis, the control-oriented model was improved for the integrated PEMFC systems. On the one hand, the anode pressure following control and cathode backpressure regulation were equivalently modeled based on analysis of interactive control characteristics of the commercial high-power integrated PEMFC systems. On the other hand, equivalent modeling of membrane hydration dynamics inside the PEMFC stack was achieved, so as to reasonably characterize the effect of liquid water saturation on the output characteristics of the commercial integrated PEMFC systems, under the premise of not significantly affecting the model complexity. Moreover, the effectiveness of the improved control-oriented model was also verified through comparing the simulation and experimental results. Further analyses based on the developed system model showed that, online evaluation and self-healing control of the membrane hydration condition can be realized through dynamic analyses of the system voltage and current according to the differential current injection method such that reasonable membrane hydration condition can be ensured. Furthermore, up to 3.74% enhancement in the system efficiency was achieved in the case of minimized membrane micro-flooding, which was of great significance to improve the service life and operation reliability of the commercial integrated PEMFC systems. [ABSTRACT FROM AUTHOR]